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/openrouter.provider.ts

@@ -124,9 +124,8 @@ export class OpenRouterExtractionProvider implements ExtractionProvider {
       body: JSON.stringify({
         model: this.config.model,
         temperature: 0,
-        // Only route to endpoints that actually honour the JSON schema. Without this,
-        // OpenRouter may pick a provider that treats it as a hint and returns prose,
-        // which fails parsing intermittently and unreproducibly.
+        // Only route to endpoints that actually honour the JSON schema — otherwise OpenRouter may
+        // pick a provider that treats it as a hint and returns prose, failing intermittently.
         provider: { require_parameters: true },
         messages: buildExtractionPrompt(transcript, catalog, localeHint),
         response_format: {