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.

docs/cookbook/adding-a-tool.i18n.yaml

@@ -1,6 +1,6 @@
 # Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
 # 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
-adding-a-tool.md: d06e3d8e3c7da1f71a55bf9c4f56cd4b2cc03697
-adding-a-tool.zh.md: 53f608eba3b26b124f873990fa13ce1572c0baf2
+#   pnpm run verify-translation-pairing --write docs/cookbook/adding-a-tool.md
+adding-a-tool.md: 75a4d87aab77c7dfcc31a1e8d0d58bc41e9e3f7e
+adding-a-tool.zh.md: ba76c14437f15b6c5381107cf2d7bd40eb5861b2