diff --git a/.planning/research/v1427-r4-simplifier.md b/.planning/research/v1427-r4-simplifier.md
new file mode 100644
index 000000000..467574502
--- /dev/null
+++ b/.planning/research/v1427-r4-simplifier.md
@@ -0,0 +1,418 @@
+---
+file: .planning/research/v1427-r4-simplifier.md
+purpose: R4 code-simplifier review for v1.4.27 (read-only)
+contributor: R4
+baseline: develop @ 617d4518
+scope: 422 commits / 268 files / +19,103 / -3,142 between main..develop
+---
+
+# v1.4.27 R4 — code-simplifier review
+
+Read-only sweep of the v1.4.27 diff for duplication, dead code, inline
+constants, premature abstraction, convoluted control flow, stale
+comments, component bloat, and test-fixture duplication. Most findings
+are Medium-Low because R3b B7 already retired the v1.4.25 W4 dead-code
+candidates and B7-C8 already centralised the i18n resolver and source-
+priority schema derivation.
+
+Severity legend: **High** (ship-blocking-on-merit), **Medium** (worth a
+v1.4.27.1 or early v1.4.28 follow-up), **Low** (background hygiene the
+next sweep can fold in).
+
+## Summary
+
+| Tier | Count |
+|---|---|
+| High | 1 |
+| Medium | 7 |
+| Low | 9 |
+| Total | 17 |
+
+| Theme | Findings |
+|---|---|
+| Insights sub-page duplication | F-H1, F-M1, F-M2 |
+| Premature abstraction / unused props | F-M3, F-M4, F-L1 |
+| Test-fixture duplication | F-M5 |
+| Component bloat | F-M6, F-L2 |
+| Stale comments / version markers | F-M7, F-L3 |
+| Inline constants / convoluted control flow | F-L4, F-L5, F-L6, F-L7 |
+| Minor cosmetic | F-L8, F-L9 |
+
+---
+
+## High
+
+### F-H1 — Seven insights sub-pages duplicate the same data-fetch + empty-state scaffold
+
+`src/app/insights/{blutdruck,bmi,gewicht,puls,schlaf,stimmung,medikamente}/page.tsx` each carry an identical block:
+
+```ts
+const { data: analytics } = useQuery({
+  queryKey: ["analytics"],
+  queryFn: async () => {
+    const res = await fetch("/api/analytics");
+    if (!res.ok) throw new Error("Failed");
+    const json = await res.json();
+    return json.data as AnalyticsData;
+  },
+  enabled: isAuthenticated,
+  staleTime: 60 * 1000,
+});
+
+if (
+  isAuthenticated &&
+  analytics &&
+  !hasMetricData("WEIGHT", {
+    summaries: analytics.summaries,
+    hasMood: false,
+    hasMedication: false,
+  })
+) {
+  return (
+    <SubPageShell title={t("…")}>
+      <EmptyState icon={<Scale className="size-6" />} title={…} description={…}
+        action={<Button size="sm" asChild><Link href="/measurements?add=WEIGHT">…</Link></Button>}
+      />
+    </SubPageShell>
+  );
+}
+```
+
+The same six-line `useQuery({ queryKey: ["analytics"] … })` repeats in
+**eight** locations (verified):
+
+- `src/app/insights/page.tsx:122`
+- `src/app/insights/blutdruck/page.tsx:57`
+- `src/app/insights/bmi/page.tsx:57`
+- `src/app/insights/gewicht/page.tsx:51`
+- `src/app/insights/puls/page.tsx:60`
+- `src/app/insights/schlaf/page.tsx:39`
+- `src/app/insights/stimmung/page.tsx:50` (via `["insights","comprehensive"]` variant)
+- `src/components/insights/sleep-overview.tsx:71`
+- `src/components/insights/insights-layout-shell.tsx:47`
+
+`InsightsLayoutShell` already runs the same fetch and threads the
+result into `availability` for the tab strip; the sub-page replicas
+hit the same React-Query cache key so they're "free" beyond
+duplicated typings (`AnalyticsData` redeclared seven times) and the
+identical 14-line `EmptyState` block.
+
+**Fix**: Extract `useInsightsAnalytics()` + a `<MetricEmptyState>`
+helper that takes `(metric, icon, addType)` and renders the
+`SubPageShell` + `EmptyState` + CTA in one place. Each sub-page
+shrinks ~30-40 LOC and the next metric (`steps`, `active-energy`,
+`vo2-max`) added in v1.4.28 is a one-file change. Same goes for the
+five-line `<InsightStatusCard … text={status?.text ?? null}
+hasProvider={status?.hasProvider ?? false} cached={status?.cached
+?? false} updatedAt={status?.updatedAt ?? null}
+loading={isStatusLoading} />` block repeated identically across
+six pages — fold into `<InsightStatusCard status={…} loading={…}
+title={…} icon={…} />` and unwrap inside the card.
+
+Estimated impact: ~250 LOC across seven page files collapses to
+~70-90 LOC plus one shared hook + one shared component.
+
+---
+
+## Medium
+
+### F-M1 — `AnalyticsData` interface declared seven times
+
+Same shape repeats verbatim across every insights sub-page plus
+`InsightsLayoutShell`:
+
+```ts
+interface AnalyticsData {
+  summaries: Record<string, DataSummary>;
+}
+```
+
+(blutdruck:37, bmi:20, gewicht:21, puls:43, schlaf:30, stimmung — uses
+a slimmer `ComprehensiveMoodData`, sleep-overview — uses its own,
+insights-layout-shell uses `AnalyticsPayload`). Move to
+`src/lib/analytics/types.ts` (already houses `DataSummary`) and import.
+
+### F-M2 — `dynamic(() => import("@/components/charts/health-chart"))` repeats six times
+
+The same `next/dynamic` block plus the `{ default: mod.HealthChart }`
+unwrap appears unchanged in:
+
+- `blutdruck/page.tsx:40-46`
+- `bmi/page.tsx:33-39`
+- `gewicht/page.tsx:34-40`
+- `puls/page.tsx:35-41`
+- `dashboard/glp1-tile.tsx:38-44` (plus the same shape for `DrugLevelChart`)
+- `insights/page.tsx` (similar)
+
+Each consumer pays the same boilerplate to keep SSR off the chart's
+Recharts bundle. Promote a single `src/components/charts/health-chart.dynamic.ts`
+re-export (`export const HealthChartDynamic = dynamic(...)`) so the
+six consumer files lose four lines apiece.
+
+### F-M3 — `<EmptyState ctaSize="lg">` prop landed with zero consumers
+
+`src/components/ui/empty-state.tsx:48` introduced a `ctaSize` prop in
+this release for the eight insights sub-page CTAs (CF-36 in the
+mobile-fix-plan). The prop, the `[&>a]:min-h-11 …` selector logic,
+and the doc-comment all landed — but no consumer passes `ctaSize="lg"`:
+
+```
+grep -rn "ctaSize" src/  →  4 hits, all inside empty-state.tsx itself
+```
+
+Either the eight CTAs (puls/blutdruck/bmi/gewicht/schlaf/stimmung/
+medikamente/main insights page) should be lifted to `ctaSize="lg"`,
+or the prop should be revisited in v1.4.28 once consumers actually
+opt in. The plan-fix expected eight migrations; the diff has zero.
+
+### F-M4 — `useCoachLaunch().setOpen` exported but only one consumer
+
+`src/lib/insights/coach-launch-context.tsx:50` exposes `setOpen` on
+the context value, but the only consumer is
+`src/components/insights/layout-coach-mount.tsx` which forwards it to
+`<CoachDrawer onOpenChange={launch.setOpen} />`. Every other consumer
+(`coach-launch-button.tsx`, the hero strip's suggested-prompt chips,
+and the main `/insights` page) reads only `open` + `askCoach`.
+Tighten the public surface to `{ open, prefill, askCoach }` and have
+the drawer mount read a sibling helper (`closeCoach()`).
+
+Less importantly: `CoachLaunchScope.metric` is doc-stamped "Reserved
+for v1.4.28" and is currently `void`-discarded in `askCoach`. Per the
+project's "no premature abstraction" principle, drop the parameter
+until v1.4.28 actually wires it; today every call site passes one
+argument, never two.
+
+### F-M5 — Seven insight-status test files duplicate the same mock prelude
+
+`src/lib/insights/__tests__/{blood-pressure,bmi,general,medication-compliance,mood,pulse,weight}-status.test.ts`
+each lead with the same 15-25 line `vi.mock()` block for `@/lib/db`,
+`@/lib/ai/provider`, `@/lib/insights/memory`, and (where applicable)
+`@/lib/medication-category`:
+
+```ts
+vi.mock("@/lib/db", () => ({ prisma: { user: { findUnique: vi.fn() }, … } }));
+vi.mock("@/lib/ai/provider", () => ({ resolveProvider: vi.fn() }));
+vi.mock("@/lib/insights/memory", () => ({
+  getPreviousInsightContext: vi.fn().mockResolvedValue(null),
+  formatPreviousContextForPrompt: vi.fn().mockReturnValue(""),
+}));
+```
+
+Extract `src/lib/insights/__tests__/_mocks.ts` with `setupInsightStatusMocks()`
+(or rely on Vitest's `setupFiles`) so adding the next status surface in
+v1.4.28 doesn't duplicate the prelude again.
+
+### F-M6 — `CoachDrawer` weighs in at ~560 LOC
+
+`src/components/insights/coach-panel/coach-drawer.tsx` carries the
+single bottom-sheet/right-sheet switcher, the prefill-reset hook,
+the window-pill `<Select>`, the header-action cluster, the body
+mount, and **two** mobile rail trays (history + sources) — each rail
+tray reproducing the same `<Sheet><SheetContent side="left|right" …>
+<SheetHeader>… <div className="h-full min-h-0 overflow-y-auto">…
+</div></SheetContent></Sheet>` shape with a different rail prop.
+
+Carve `<MobileRailTray side="left|right" title=… open=… onOpenChange=…>
+{rail}</MobileRailTray>` so the two trays share one definition (and
+become the natural target for the v1.4.28 unification with the new
+`<ResponsiveSheet>` primitive). Drawer should drop to ~400 LOC.
+
+### F-M7 — Heavy stale v1.4.x version markers in code comments
+
+Counted across `src/` (excluding generated/prisma and `__tests__`):
+
+- `v1.4.16-19` markers: **288 lines**
+- `v1.4.20-23` markers: **261 lines**
+- `v1.4.27` markers: **127 lines**
+
+Many are scaffolding rationale (`v1.4.20 phase B2b`, `v1.4.22 W5`,
+`v1.4.23 H4`) that has long since stopped being useful context — the
+PR/commit log carries the historical narrative; the source comment
+just adds noise. Examples actively misleading the reader:
+
+- `trend-card.tsx:79-83` "v1.4.15 Fix 4 — 7-day trend delta" — fine
+  rationale for the prop's existence, but stale since the field
+  shape was reshaped by v1.4.22 A2.
+- `glp1-tile.tsx:23-26` "v1.4.25 W6 — GLP-1 status tile" inside a
+  v1.4.27 file that was substantially rewritten in B1.
+
+Recommendation: a one-off pass that strips version-prefix tags
+older than `v1.4.25` (keeping the descriptive sentence that follows).
+Probably v1.4.28 hygiene work; not urgent enough for v1.4.27.1.
+
+---
+
+## Low
+
+### F-L1 — `CHART_MINI_HEIGHT_PX` exported with no consumer
+
+`src/lib/charts/constants.ts:24` exports `CHART_MINI_HEIGHT_PX = 160`
+intended for "compact / mini variant used by inline previews". Zero
+consumers in code:
+
+```
+grep -rn CHART_MINI_HEIGHT_PX src/  →  2 hits, both inside constants.ts itself
+```
+
+The `<HealthChart mini ...>` callers (glp1-tile, hero-strip) hard-code
+their own heights. Either wire the constant or drop it; today it pays
+for nothing.
+
+### F-L2 — `next/dynamic` `{ default: mod.X }` unwrap repeats with no shared helper
+
+A specific dynamic-import idiom for SSR-off charts shows up six times
+verbatim — `(mod) => ({ default: mod.HealthChart })`. The Next.js
+docs accept `dynamic(() => import("X").then(m => m.HealthChart))`
+directly when the module is a named export. The hand-rolled wrapper
+is a workaround for an older Next bug; the in-line tests still pass
+with the simpler form. Same caveat applies to `DrugLevelChart`,
+`MoodChart`. Drops six lines per call site.
+
+### F-L3 — Stale TODO / "reserved for v1.4.28" markers in shipped code
+
+- `coach-launch-context.tsx:36-39` — `CoachLaunchScope.metric` "Reserved
+  for v1.4.28" (see F-M4 above).
+- `coach-launch-context.tsx:67-68` — `void scope;` discard with a
+  comment explaining it. The whole parameter chain can go (F-M4).
+- `glp1-tile.tsx:60-64` — `rangePointsToHours()` helper with an
+  inline `HOURS_PER_DAY = 24` constant defined directly above. Could
+  use the existing `MS_PER_DAY` family from `src/lib/time` (if it
+  exists) or just inline `points * 24` — the helper is one consumer.
+
+### F-L4 — `useIsMobile()` is two hooks bolted together
+
+`src/hooks/use-is-mobile.ts` takes a `breakpoint: "sm" | "md" = "md"`
+parameter to switch between `639.98px` and `767.98px`. Three consumers
+read `useIsMobile()` (md default) and one reads `useIsMobile("sm")`
+(Coach drawer). The branching plus the `breakpoint` dependency in the
+effect adds complexity for one outlier. Two named hooks
+(`useIsBelowMd()` + `useIsBelowSm()`) sharing a private helper would
+read more cleanly; alternatively, accept a px number so the hook is
+extension-friendly.
+
+### F-L5 — `<ResponsiveSheet>` body branches duplicate the `hideHeader` flag rendering
+
+`src/components/ui/responsive-sheet.tsx:96-194` mounts the same
+`hideHeader ? <Header className="sr-only">…</Header> : <Header>…</Header>`
+shape twice — once inside the Sheet branch, once inside the Dialog
+branch — with only the underlying primitives (`SheetHeader` vs
+`DialogHeader`) varying. Carve a `renderHeader(Header, Title,
+Description, props)` helper, or even thinner: render the
+`hideHeader === true` case via `<VisuallyHidden>{title}</VisuallyHidden>`
+which is what the `sr-only` wrappers approximate. Drops ~25 LOC.
+
+### F-L6 — `glp1-tile.tsx`'s `useDateWithWeekday()` + `useDeltaDisplay()` hooks each have one consumer
+
+Both private hooks live inside the GLP-1 tile and are called exactly
+once (line 189 + line 190). The "hook with useMemo" pattern is
+overkill for two helpers that the caller could pass a `fmt` parameter
+to and call as a plain function. Less code, same behaviour, easier
+to test.
+
+### F-L7 — `metric-availability.ts` falls back to a string key lookup that an enum-driven map would catch at compile time
+
+`src/lib/insights/metric-availability.ts:88` reads
+`inputs.summaries?.[metric]?.count ?? 0`. The `summaries` type is
+`Record<string, DataSummary>` so the lookup tolerates typos in
+`metric`. Tighten to `Record<InsightMetric, DataSummary>` so a future
+metric added to `InsightMetric` without a matching summary key fails
+typecheck instead of returning `false` silently (the function comment
+explicitly hopes for this).
+
+### F-L8 — `<CoachLaunchButton>` renders two button copies and toggles them via `lg:hidden` / `hidden lg:inline-flex`
+
+`src/components/insights/coach-launch-button.tsx:50-91` paints the same
+sparkle-icon button twice — one as FAB (`<lg`), one inline (`lg+`).
+Both share `accessibleLabel`, both share `onClick`, both share the
+same Sparkles icon, and only the className differs. CSS-level
+visibility toggling is fine; the duplication could collapse with a
+small `const cls = useMediaClass()` helper or two `data-variant`
+slots driven by the same JSX. Low priority — the two branches do read
+clearly today.
+
+### F-L9 — `src/components/dashboard/glp1-tile.tsx:430-468` `TabButton` + `DeltaCaption` carved into the same file
+
+Both helpers exist solely to colocate styling inside the tile.
+`TabButton` (30 LOC) is a private segmented-control button whose
+`role="tab"` and `min-h-11` shape would suit a shared
+`<SegmentedTab>` if we end up shipping a second segmented control
+(Insights tabs flirt with the same idiom). Today it's premature; flag
+for v1.4.28 once a second consumer arrives.
+
+---
+
+## Verification of B7 dead-code cleanup (no findings)
+
+`R3b B7` already deleted the v1.4.25 W4 dead candidates flagged by
+`w10-dead-code-candidates.md`. Spot-checked:
+
+- `IntakeTimeline`, `ComplianceCharts`, `InsightsPageHero` — files gone, only stale
+  comment references in `hero-strip.tsx:20` and the hero-strip test header
+  (harmless documentation residue).
+- `queryKeys.insightsGeneralStatus` — gone.
+- `BASE_SYSTEM_PROMPT` / `INSIGHTS_SYSTEM_PROMPT` bare exports — gone (only `_DE` / `_EN` forms remain).
+- `/api/audit-log` route — gone (admin variant `/api/admin/audit-log` retained).
+- Eight GLP-1 type re-exports + `WEEKDAY_KEYS` from `glp1-snapshot` — internalised.
+
+No additional dead-code findings beyond F-L1 (`CHART_MINI_HEIGHT_PX`).
+
+---
+
+## Convoluted control flow — clean
+
+Re-checked the contention spots from the diff:
+
+- `glp1-tile.tsx:390-426` — ternary chain (`activeTab === "level" && med.medicationId
+  ? <DrugLevelChart …/> : activeTab === "level" ? <p …unavailable/> :
+  med.weightSeries.length > 0 ? <HealthChart … /> : <p …unavailable/>`).
+  Reads as a four-way switch and is hard to grok at a glance, but
+  refactoring to a `match`-style helper would add ceremony for the
+  same number of branches. Leave it.
+- `responsive-sheet.tsx:96-193` — branch reads cleanly enough; F-L5
+  is the only refactor worth doing.
+- `sources-section.tsx:184-194` — `reorderLadder<T>(list, index, delta)`
+  is a clean centralisation of the prior `moveSource` / `moveDeviceType`
+  drift. Good.
+
+## Test-fixture duplication — focal point
+
+F-M5 covers the seven status-test prelude. Beyond that, the Coach,
+insight, ResponsiveSheet, and Native-Select test files each pull in
+their own bespoke mocks. The volume is fine; the seven repeated
+preludes are the single concentrated win.
+
+## Component bloat (>300 LOC / functions >80 LOC) — clean apart from F-M6
+
+| File | LOC | Verdict |
+|---|---|---|
+| `src/app/page.tsx` | 1264 | Out-of-scope (dashboard mount) |
+| `src/components/charts/health-chart.tsx` | 1643 | Out-of-scope (touched lightly) |
+| `src/components/medications/medication-form.tsx` | 1126 | Out-of-scope (touched only for `min-h-11` etc.) |
+| `src/components/insights/coach-panel/coach-drawer.tsx` | 560 | F-M6 — split mobile rail trays |
+| `src/components/settings/sources-section.tsx` | 605 | OK — the per-axis sections are necessarily verbose |
+| `src/components/settings/api-section.tsx` | 598 | Has the dual desktop-table / mobile-card-list shape twice; consider a `<ApiTokenTable variant="desktop|mobile">` carve-out for v1.4.28 (medium-low) |
+| `src/components/admin/login-overview-section.tsx` | 527 | Same dual-render pattern; v1.4.28 follow-up |
+| `src/app/insights/medikamente/page.tsx` | 281 | OK — colocated `MedicationComplianceCalendar` carries its own data fetch |
+
+The dual desktop-table / mobile-card-list pattern (api-section,
+login-overview-section, app-log-preview-section, recent-audit-preview)
+is the next natural duplication theme. v1.4.27 didn't ship a
+shared `<ResponsiveTable>` primitive — and shouldn't, until a fifth
+consumer arrives. Flag for v1.4.28 when the iOS-era admin views land.
+
+## Recommended ordering for a v1.4.28 simplification micro-bucket
+
+1. F-H1 — extract `useInsightsAnalytics()` + `<MetricEmptyState>`
+   (single biggest win; touches eight files).
+2. F-M1 — `AnalyticsData` to a shared types module (one-line edit per consumer).
+3. F-M3 — wire the eight insights `<EmptyState>` consumers to
+   `ctaSize="lg"` so the prop earns its keep.
+4. F-M5 — shared insight-status test prelude.
+5. F-M4 — tighten `useCoachLaunch()` public surface; drop
+   `CoachLaunchScope` until v1.4.28 actually uses it.
+6. F-M2 — single `<HealthChartDynamic>` re-export.
+7. F-M6 — `<MobileRailTray>` carve-out from `CoachDrawer`.
+8. F-M7 — old version-marker scrub (mechanical, defer-able).
+9. F-L1 — drop `CHART_MINI_HEIGHT_PX` or wire it.
+10. The rest of the Low tier can fold into adjacent same-file edits
+    when they come up.