feat(medications): promote the detail page to a tabbed shell

Make /medications/[id] the canonical full-page home for one medication:
a Radix tab strip (Übersicht · Zeitplan · Erinnerung · Bestand · Verlauf ·
Injektion · Erweitert) with ?tab= URL state, a read-only hero, and a
"Vollständig bearbeiten" jump into the wizard for structural edits.
Everyday levers move inline into the tabs.

Übersicht surfaces the adherence bars, Erinnerung owns notifications +
reminder grace, Bestand reads the pen/vial inventory (all medications,
calm empty state), Verlauf renders the editable intake history, and
Injektion (injectable routes only) carries the existing GLP-1 charts +
side-effect log. The ledger, the per-dose window editor and the
injection body-map land in the following waves.

The legacy /medications/[id]/history route now redirects to ?tab=verlauf
for bookmarks and deep links. Tab labels are i18n across six locales.

src/lib/query-keys.ts

@@ -265,6 +265,13 @@ export const queryKeys = {
     ["medications", medicationId, "cadence"] as const,
   medicationGlp1Details: (medicationId: string) =>
     ["medications", medicationId, "glp1-details"] as const,
+  /**
+   * v1.15.18 — per-medication pen/vial inventory list, consumed by the
+   * detail page's Bestand (supply) tab. Rides under the `["medications"]`
+   * prefix so an intake mutation that decrements a pen invalidates it.
+   */
+  medicationInventory: (medicationId: string) =>
+    ["medications", medicationId, "inventory"] as const,
   medicationIntakeDrugLevelChart: (medicationId: string) =>
     ["medications", medicationId, "intake", "drug-level-chart"] as const,
   /**