docs: cut the comments that were not earning their place

I wrote 731 comment lines on this branch against 4,530 lines of code — 14%,
where the rest of the repo runs at 1.8%. CLAUDE.md asks for code that reads
like its surroundings, and this did not.

Removed by genre rather than by taste:

- restating the code, e.g. "JS getUTCDay() numbering: Sunday = 0" above the
  map that literally shows it, and a docblock on startOfWeek explaining that
  it returns the start of the week;
- narrating history — "this used to rebuild the whole map", "left the bar
  recording forever" — which the commit message and git blame already carry;
- saying the same thing in several places: the "cannot record is not a
  denied microphone" reason appeared three times in one file, and the
  "aborting stops a per-minute metered call" reason across three files. Each
  now lives once, where the behaviour it explains lives;
- defending decisions nobody would question, like why toLatinDigits is its
  own module;
- over-explaining defensive branches, three separate comments to distinguish
  null from missing-kind from unrecognised-kind.

What stays is what the code cannot say: the patient-right convention in
toFdi, whose failure mode is a valid code for the wrong tooth; the
"this"-vs-"next" week anchoring; StrictMode re-arming mountedRef; Safari
accepting no mimeType hint; and the invariants whose violation already cost
a bug — the body parser's middleware ordering and the dispatch panel's
auto-fill rules.

Comments only. The diff contains no non-comment line.

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

backend/src/modules/voice/due-date.resolver.ts

@@ -15,7 +15,6 @@ import type { DueIntent, UnresolvedItem, Weekday } from './voice.types';
  * to reason about instants.
  */
 
-/** JS `getUTCDay()` numbering: Sunday = 0. */
 const WEEKDAY_TO_JS: Record<Weekday, number> = {
   saturday: 6,
   sunday: 0,
@@ -26,7 +25,6 @@ const WEEKDAY_TO_JS: Record<Weekday, number> = {
   friday: 5,
 };
 
-/** Refuse absurd deadlines however they were arrived at. */
 const MAX_DAYS_AHEAD = 365 * 5;
 
 export type DueResolution = {
@@ -78,12 +76,9 @@ function unresolved(spoken: string): DueResolution {
 }
 
 /**
- * What to quote back when a deadline could not be resolved.
- *
- * Every field here is nullable on the wire and `toVoiceIntent` casts rather than checks,
- * so a half-classified deadline arrives with nulls in it. The review sheet renders this
- * verbatim — `"null null" — not a usable date` in front of a clinician is worse than the
- * reason on its own, which the sheet already handles for a blank string.
+ * What to quote back when a deadline could not be resolved. Every field is nullable on the
+ * wire and `toVoiceIntent` casts rather than checks, and the sheet renders this verbatim —
+ * so a half-classified deadline must fall back to '', not to `"null null"`.
  */
 function describe(intent: DueIntent): string {
   const usable = (value: unknown): value is number =>
@@ -108,8 +103,7 @@ function describe(intent: DueIntent): string {
         ? `${intent.y}-${intent.m}-${intent.d}`
         : '';
     default: {
-      // Reaching here means an unrecognised `kind`, which resolveDueDate has already
-      // established is a string — echo it so the review row names what was heard.
+      // An unrecognised `kind`, already established as a string — echo what was heard.
       const kind = (intent as { kind?: unknown })?.kind;
       return typeof kind === 'string' ? kind : '';
     }
@@ -117,11 +111,9 @@ function describe(intent: DueIntent): string {
 }
 
 /**
- * Which weekday starts the week, per locale.
- *
  * "Next Thursday" is week-relative, so this changes the answer: the Iranian week starts
- * Saturday, the Dutch and (European) English week starts Monday. Hardcoding Saturday
- * would put an en/nl clinician's deadline a week out.
+ * Saturday, the Dutch and English week Monday. Hardcoding either puts the other locale's
+ * deadline a week out.
  */
 const WEEK_START_BY_LOCALE: Record<string, number> = {
   fa: WEEKDAY_TO_JS.saturday,
@@ -135,22 +127,18 @@ export function weekStartForLocale(locale: string): number {
   return WEEK_START_BY_LOCALE[locale] ?? DEFAULT_WEEK_START;
 }
 
-/** Most recent week-start day, counting today if today is that day. */
 function startOfWeek(iso: string, weekStartJs: number): string {
   const back = (civilDateJsWeekday(iso) - weekStartJs + 7) % 7;
   return addDays(iso, -back);
 }
 
 /**
- * `'this'` is occurrence-anchored: the soonest occurrence strictly after today, so "by
- * Thursday" said on a Thursday means the next one — a deadline of today is almost never
- * what was meant, and this can never resolve into the past.
+ * `'this'` is occurrence-anchored: the soonest occurrence strictly after today, so it can
+ * never resolve into the past.
  *
- * `'next'` is *week*-anchored, not "this plus seven". "Thursday next week" means the
- * Thursday of the Saturday-start week after this one; adding a week to `'this'` would
- * overshoot by seven days whenever `'this'` had already rolled into next week. The two
- * can legitimately coincide — said on a Thursday, "the coming Saturday" and "Saturday
- * next week" are the same day.
+ * `'next'` is *week*-anchored, not "this plus seven" — adding a week to `'this'` overshoots
+ * by seven days whenever `'this'` has already rolled into next week. The two legitimately
+ * coincide: said on a Thursday, "the coming Saturday" and "Saturday next week" are one day.
  */
 function resolveWeekday(
   intent: Extract<DueIntent, { kind: 'weekday' }>,
@@ -199,18 +187,15 @@ export function resolveDueDate(
   todayIso: string,
   weekStartJs: number = DEFAULT_WEEK_START,
 ): DueResolution {
-  // Absent is not an error — most utterances carry no deadline. Anything else that is not
-  // an intent object is a deadline we failed to understand, and must be flagged rather
-  // than silently dropped.
+  // Absent is not an error — most utterances carry no deadline.
   if (intent === null || intent === undefined) {
     return { dueDate: null, unresolved: null };
   }
   if (typeof intent !== 'object') {
     return unresolved(String(intent).slice(0, 120));
   }
-  // An object carrying no `kind` at all says nothing about a deadline; flagging it would
-  // put a blank "heard but lost" row in front of a clinician who never mentioned one. An
-  // object with an *unrecognised* kind did try to say something, and is flagged below.
+  // No `kind` at all says nothing about a deadline, so it is not "heard but lost". An
+  // *unrecognised* kind did try to say something, and is flagged below.
   if (typeof (intent as { kind?: unknown }).kind !== 'string') {
     return { dueDate: null, unresolved: null };
   }
@@ -240,8 +225,7 @@ export function resolveDueDate(
 
   if (!resolved) return unresolved(describe(intent));
 
-  // An absolute date the model invented can land anywhere; a deadline in the past or
-  // decades away is not a deadline.
+  // A date the model invented can land anywhere; past or decades away is not a deadline.
   const daysAhead = (utcMsOf(resolved) - utcMsOf(todayIso)) / 86_400_000;
   if (daysAhead < 0 || daysAhead > MAX_DAYS_AHEAD)
     return unresolved(describe(intent));