refactor(fs): minimize and cap search card meta; keep TUI byte-identical

Address the review of the search render card:

- The search result view carries no `content`: it was a no-op for every
  consumer and serialized the whole search text twice. A UI without a search
  card falls back to the raw tool/result content; the TUI stays byte-identical
  to the pre-search-card generic fallback.
- Bound the serialized presentationMeta with a configurable searchMetaMaxBytes
  (default 64 KiB): the inline item cap does not bound bytes, and spill-policy
  only shrinks content, never meta. capMetaBytes drops trailing groups/paths.
- Share one retention pass (retainGrepMatches/retainGlobPaths in search-core)
  between the model-facing render and the meta projection; remove the second
  cap/preview implementation and the presentation<->grep module cycle by
  moving GrepMatch/previewLine to search-core.
- Rename the result-view discriminant kind -> shape so it no longer collides
  with GenericCallView.kind (ToolCallKind, whose values include 'search').
- Narrow the entry export surface to consumed symbols.
- Sync the three bilingual ToolResultView doc pairs and the Agent Note pair;
  document the deliberate empty-card acceptance vs diffsFromMeta.
- Regenerate config/tool/cordis catalogs for the new config field.

packages/core/tools/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/core/tools/README.md
-README.md: e5adb153e77d7a2d8c4068b016194ab6abb6473e
-README.zh.md: c67a2f2ee4ac2a9d587c6efbf2b5c60d14fc58c2
+README.md: a8afab7839983d300c2c17627e34dafaa4648d8b
+README.zh.md: 8beb63e8376f397ac859a6a04ab2f35316ef6d27