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/core-data-structures/tools.md

@@ -447,7 +447,7 @@ type ObjectJsonSchema = JsonSchemaNode & { type: 'object' }
 How a tool wants its call shown in a UI (an editor tool-call card, a CLI log line), provider-neutral so a tool describes itself without depending on any client protocol. `presentCall`/`presentResult` return a **`card`-tagged render intent** — a discriminated union a UI bridge switches on:
 
 - `ToolCallView` (pending): `{ card: 'generic', title, kind?, rawInput?, content?, locations? }` (the default card; `locations` is `{ path, line? }[]` files the call reads/modifies, for editor follow-along), `{ card: 'terminal', title, description?, cwd? }` (a shell command → a terminal card), or `{ card: 'diff', title, diffs, locations? }` (a file create/modify → an inline diff card; `diffs` is `{ path, oldText, newText }[]`, `oldText: null` for a new file).
-- `ToolResultView` (completed): `{ card: 'generic', title?, content? }`, `{ card: 'terminal', title?, output?, exitCode?, signal? }` (the captured run output + exit; a capable UI shows an exit-status pill, while another may derive a fenced ` ```console ` fallback), or `{ card: 'diff', title?, diffs }` (a completed file mutation → the change to show, typically the applied hunks with context lines computed from the before/after content, or a whole-file diff when there is no before-image). Completed views replace pending views, so mutation tools return a diff result even when it duplicates the call-time snippet.
+- `ToolResultView` (completed): `{ card: 'generic', title?, content? }`, `{ card: 'terminal', title?, output?, exitCode?, signal? }` (the captured run output + exit; a capable UI shows an exit-status pill, while another may derive a fenced ` ```console ` fallback), `{ card: 'diff', title?, diffs }` (a completed file mutation → the change to show, typically the applied hunks with context lines computed from the before/after content, or a whole-file diff when there is no before-image), or `{ card: 'search', shape, title?, truncated, total, … }` (a completed discovery search → grouped-by-file matches for `shape: 'matches'` (grep) or a flat path list for `shape: 'paths'` (glob); `truncated`/`total` report whether the inline result was capped so a UI never presents a partial result as complete; the view carries no result text — a UI without a search card falls back to the raw result content). Completed views replace pending views, so mutation tools return a diff result even when it duplicates the call-time snippet; a search has no `card: 'search'` call-time analogue (its pending state stays a generic card, since matches exist only after `execute`).
 
 `ToolCallKind` (`'read' | 'edit' | 'delete' | 'move' | 'search' | 'execute' | 'fetch' | 'other'`) picks an icon on a generic card. `FileLocation` (`{ path, line? }`) and `FileDiff` (`{ path, oldText, newText }`) are the shared file-card vocabulary. The design is pinned in [the render-intent-union Agent Note](../../.agents/notes/implemented/architecture/2026-07-02-tool-render-intent-union.md); the TUI and host/client runtime project this neutral vocabulary into their own views.