chore: drop context module — registry refs, schema, AI route, AppId

The context module's UI + Dexie tables + i18n bundle were already
removed in d3e2e73ca. This follow-up cleans up everything else that
still referenced it:

- API: rename POST /api/v1/context/import-url → /api/v1/kontext/import-url
  (the kontext singleton was the only consumer); drop the unused
  /ai/generate + /ai/estimate endpoints; rename the credit-op label
  AI_CONTEXT_IMPORT_URL → KONTEXT_IMPORT_URL; drop AI_CONTEXT_GENERATION
  from packages/credits.
- Web: drop registerApp + File icon import from app-registry/apps.ts;
  drop contextModuleConfig from data/module-registry.ts (+ snapshot test);
  drop useRecentDocuments + useSpaces from cross-app-queries.ts; drop
  ContextDocsWidget from widget-registry + dashboard.svelte.ts +
  types/dashboard{,.test}.ts; drop dashboard.widgets.context from all 5
  dashboard locales; drop context entries from hooks.server allowlist,
  splitscreen registry, observatory mockData, spiral collect, crypto
  registry + plaintext-allowlist.
- Dexie: remove documents/contextSpaces/documentTags from v1, v31, v53
  stores blocks; add v57 dropping the three tables on local dev DBs
  that already ran an earlier schema.
- Shared-branding: drop 'context' from AppId union, APP_BRANDING,
  MANA_APPS, APP_ICONS (+ contextSvg), ContextLogo.svelte (+ logos
  barrel re-export).
- Spiral-DB: drop context: 10 from MANA_APP_INDEX (slot now free).
- i18n hardcoded-string baseline: drop 5 context routes/files.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/api/src/index.ts

@@ -96,6 +96,7 @@ const RESOURCE_MODULES = [
 	'chat',
 	'food',
 	'guides',
+	'kontext',
 	'news-research',
 	'notes',
 	'picture',