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+# R3d MB4 — Coach reachability + mobile chrome
+
+Owner of CF-3, CF-9, CF-11 (verified), CF-31 (verified), CF-40, CF-73, CF-74.
+Branch: `develop`. Pass-1 (MB1/MB2/MB3) landed before any MB4 work.
+
+## What landed
+
+Four atomic commits on `develop`, all gates green.
+
+1. `246c1def` — `feat(coach): mount the drawer at the insights layout with a launch context`
+   - New `<CoachLaunchProvider>` in `src/lib/insights/coach-launch-context.tsx`
+     exposes `useCoachLaunch() → { open, prefill, askCoach, setOpen }`.
+   - New `<LayoutCoachMount>` client bridge renders the `<CoachDrawer>`
+     beside the provider so the `insights/layout.tsx` server file stays
+     server-side.
+   - `src/app/insights/layout.tsx` now wraps every routed sub-page in
+     `<CoachLaunchProvider>` + mounts the drawer.
+   - `src/app/insights/page.tsx` consumes the context instead of an
+     inline `useState` + `<CoachDrawer>` pair.
+   - Each of the seven sub-pages (`blutdruck`, `gewicht`, `puls`,
+     `stimmung`, `medikamente`, `bmi`, `schlaf`) mounts a new
+     `<CoachLaunchButton>` — sticky FAB on `<lg`, inline action on `lg+`.
+   - Smoke contract for the provider in
+     `src/lib/insights/__tests__/coach-launch-context.test.tsx`
+     (3 tests; verifies hook shape + provider mount + null fallback).
+
+2. `79dbdfbd` — `feat(coach): hide the drawer window pill on phone viewports and pin title truncation`
+   - Wraps the drawer header's window-pill `<Select>` in a
+     `hidden sm:block` container. Phone users reach the same override
+     via the sources-rail picker (right-edge tray).
+   - Pins `min-w-0` on `<SheetTitle>` so very long titles always clip.
+   - The bottom-sheet branch on `<sm` was already wired in MB1
+     (the drawer reads `useIsMobile("sm")` to flip side="bottom") so
+     CF-9 needed no further edits here.
+
+3. `40916d31` — `feat(coach): swap the sources-rail toggle to a shadcn Checkbox`
+   - New primitive `src/components/ui/checkbox.tsx` (shadcn pattern
+     backed by `radix-ui`'s `Checkbox` namespace).
+   - `sources-rail.tsx` drops its raw `<input type="checkbox">` for the
+     new `<Checkbox>` — keyboard contract (Space toggles, Tab moves),
+     focus ring, touch-friendly hit target. Existing sources-rail tests
+     still pass (the `data-slot="coach-sources-checkbox"` marker is
+     preserved on the primitive).
+
+4. `650d4f8e` — `feat(coach): re-pin the message-thread scroll when the soft keyboard opens`
+   - `message-thread.tsx` adds a `window.visualViewport.resize`
+     listener with the same wasPinned guard as the existing
+     scroll-on-message effect. When the soft keyboard slides in the
+     thread re-pins to the bottom so the tail stays visible.
+
+## CF coverage
+
+- CF-3 — drawer mount move + provider — **done** (commit 1).
+- CF-9 — bottom-sheet on `<sm` — **already landed in MB1**, verified.
+- CF-11 — history-rail delete reveal — **already landed in MB2**,
+  verified (history-rail.tsx ships the always-visible `<Button>` with
+  the `data-confirming` confirmation styling; no further edit needed).
+- CF-31 — info-icon popover — **already landed in MB3**, verified
+  (coach-input.tsx swapped Tooltip → Popover at the composer hint).
+- CF-40 — sources-rail Checkbox swap — **done** (commit 3).
+- CF-73 — SheetTitle truncate — **done** (commit 2 — `min-w-0 truncate`).
+- CF-74 — visual viewport scroll re-pin — **done** (commit 4).
+
+## Tests
+
+- Smoke contract for the new context — 3 tests, all green.
+- `pnpm vitest run src/components/insights src/lib/insights` →
+  **51 files / 471 tests passed**.
+- `npx tsc --noEmit` → clean.
+- `npx eslint src/components/insights src/lib/insights src/components/ui/checkbox.tsx src/app/insights` → clean.
+
+## Files touched (final)
+
+New:
+- `src/lib/insights/coach-launch-context.tsx`
+- `src/lib/insights/__tests__/coach-launch-context.test.tsx`
+- `src/components/insights/coach-launch-button.tsx`
+- `src/components/insights/layout-coach-mount.tsx`
+- `src/components/ui/checkbox.tsx`
+
+Modified:
+- `src/app/insights/layout.tsx` (provider + drawer mount)
+- `src/app/insights/page.tsx` (consume context, drop inline mount)
+- `src/app/insights/blutdruck/page.tsx`
+- `src/app/insights/gewicht/page.tsx`
+- `src/app/insights/puls/page.tsx`
+- `src/app/insights/stimmung/page.tsx`
+- `src/app/insights/medikamente/page.tsx`
+- `src/app/insights/bmi/page.tsx`
+- `src/app/insights/schlaf/page.tsx`
+- `src/components/insights/coach-panel/coach-drawer.tsx` (window-pill +
+  SheetTitle)
+- `src/components/insights/coach-panel/sources-rail.tsx` (Checkbox swap)
+- `src/components/insights/coach-panel/message-thread.tsx`
+  (visualViewport listener)
+
+## Coordination notes
+
+- The branch HEAD moved a lot during this bucket (multiple sibling
+  buckets landing in parallel). The MB4 commits sit on top cleanly;
+  no merge conflicts and the sub-page edits (CoachLaunchButton
+  mounts) survived MB6's empty-state CTA href swaps intact because
+  the touch zones were disjoint (imports + body tail vs the
+  EmptyState block).
+- `<CoachLaunchProvider>` returns `null` from `useCoachLaunch()` when
+  consumed outside the provider so the launch button degrades to
+  rendering nothing rather than crashing on a non-Insights surface.
+- The `scope` argument on `askCoach(prefill, scope)` is currently
+  reserved (the parameter is accepted but the rail does not yet
+  pre-narrow to a metric); ready for v1.4.28 to wire when the
+  sources-rail starts honouring per-metric narrowing.