fix(browse): sanitize lone Unicode surrogates at commandResult chokepoint + /batch envelope (#1440)

Page captures with mixed-script Unicode round-trip cleanly to the Claude API.
Two new utilities in browse/src/sanitize.ts: stripLoneSurrogates for raw UTF-16
strings, stripLoneSurrogateEscapes for \uXXXX JSON escape text. sanitizeBody
picks the right pass based on cr.json.

buildCommandResponse is extracted from handleCommand (now exported) and
applies sanitization before new Response(). /batch was bypassing this
chokepoint via direct JSON.stringify, so it sanitizes each cr.result before
pushing AND wraps the envelope with stripLoneSurrogateEscapes. Defense in
depth wraps at getCleanText, getCleanTextWithStripping, html, accessibility,
and snapshot.ts return points so downstream consumers (datamarking, envelope
wrapping) see sanitized text before the response is built.

25 new unit tests across sanitize.test.ts and build-command-response.test.ts.
content-security.test.ts updated to accept either pre- or post-sanitize form
of the snapshot scoped branch (source-level regression check).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/resolvers/index.ts

@@ -22,6 +22,7 @@ import { generateModelOverlay } from './model-overlay';
 import { generateGBrainContextLoad, generateGBrainSaveResults } from './gbrain';
 import { generateQuestionPreferenceCheck, generateQuestionLog, generateInlineTuneFeedback } from './question-tuning';
 import { generateMakePdfSetup } from './make-pdf';
+import { generateTasksSectionEmit, generateTasksSectionAggregate } from './tasks-section';
 
 export const RESOLVERS: Record<string, ResolverFn> = {
   SLUG_EVAL: generateSlugEval,
@@ -77,4 +78,6 @@ export const RESOLVERS: Record<string, ResolverFn> = {
   QUESTION_LOG: generateQuestionLog,
   INLINE_TUNE_FEEDBACK: generateInlineTuneFeedback,
   MAKE_PDF_SETUP: generateMakePdfSetup,
+  TASKS_SECTION_EMIT: generateTasksSectionEmit,
+  TASKS_SECTION_AGGREGATE: generateTasksSectionAggregate,
 };