feat: wire voice entry into the treatment workspace

Makes the feature reachable end to end: availability is fetched alongside the
catalogs, the capture hook drives the segmented control, and confirming the
review sheet appends a new detail.

Confirm always appends — it never edits an existing detail and never calls
onAddDetail. Ticked rows land on top of the seeded defaults, so unticking the
type row leaves the appointment-purpose default rather than a blank. Lab-side
rows ride on a lab case draft keyed by the detail's *client* id, so a brand-new
unsaved detail can carry a lab, due date and per-tooth prosthesis map.

Availability comes from the API rather than a NEXT_PUBLIC_* var, since those are
baked in at build time; a failure fetching it degrades to no microphone rather
than taking the treatment tab down.

From review of this commit:

- Unticking "teeth" while leaving "prosthesis" ticked attached prosthesis rows
  for teeth the detail does not contain. Nothing downstream filters them —
  assertCompleteToothProsthesisMap only checks detail-teeth ⊆ map, never the
  reverse — so they would have reached task generation as lab work for teeth
  nobody is treating. The map is now filtered to the detail's own teeth.
- The microphone was gated on the URL locale while the server resolved
  everything from req.user.language. Those diverge (a bookmarked /fa/ URL, a
  language toggle whose save failed), which would transcribe Persian with an
  English hint and anchor "next Thursday" to a Monday week instead of a Saturday
  one — or 403 from a visibly-enabled button. The client now sends the locale the
  microphone was offered in, so the gate and the request agree by construction.

Also fixed from the previous review: a civil YYYY-MM-DD date rendered a day
early west of Greenwich (parsed as UTC midnight); the missing-teeth list
hardcoded the Arabic comma for all locales; and voiceApply had no ICU plural, so
the common single-field case read "Apply 1 fields".

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

frontend/src/lib/api/voice.ts

@@ -8,6 +8,8 @@ export interface ExtractVoicePayload {
   /** IANA zone — the server derives "today" from it for relative deadlines. */
   timeZone: string;
   durationMs: number;
+  /** Locale the clinician is speaking; the server uses it rather than the stored one. */
+  locale: string;
 }
 
 export const voiceApi = {

frontend/src/lib/voice/useVoiceCapture.ts

@@ -12,6 +12,8 @@ import {
 } from './audioFormat';
 
 export interface UseVoiceCaptureOptions {
+  /** The locale the clinician is speaking, sent so the server does not have to guess. */
+  locale: string;
   /** null means uncapped; otherwise the recorder auto-stops here. */
   maxMs: number | null;
   onExtracted: (result: VoiceExtractionResult) => void;
@@ -46,6 +48,7 @@ function clientError(code: string): ApiError {
  * and receives only a `voice` prop, so MediaRecorder and the API call never enter ui/.
  */
 export function useVoiceCapture({
+  locale,
   maxMs,
   onExtracted,
   onError,
@@ -117,6 +120,7 @@ export function useVoiceCapture({
             format: mimeTypeToFormat(mimeType),
             timeZone: Intl.DateTimeFormat().resolvedOptions().timeZone,
             durationMs,
+            locale,
           },
           controller.signal,
         );
@@ -131,7 +135,7 @@ export function useVoiceCapture({
         setElapsedMs(0);
       }
     },
-    [onExtracted, onError],
+    [locale, onExtracted, onError],
   );
 
   const stop = useCallback(() => {