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.zh.md

@@ -78,6 +78,7 @@ producer 提供同步的 `cancel`、在资源清理后 settle 且不 reject 的
   - `generic` 提供可选的标题和内容。
   - `terminal` 提供原始输出和可选的退出元数据；各 UI 根据自身能力渲染对应视图或回退视图。
   - `diff` 提供已应用的 hunk，通常由 `output.presentationMeta` 派生并通过持久化的 `result.meta` 携带，使回放能重现它们。变更类工具保留 diff 结果，因为完成后的视图会替换 pending 卡片。
+  - `search` 提供从持久化 `result.meta` 重建的发现型结果：按文件分组的匹配（`shape: 'matches'`，grep）或扁平路径列表（`shape: 'paths'`，glob），外加 `truncated`/`total` 使 UI 永不把被截断的结果当作完整结果呈现。该视图不携带结果文本（无 search 卡片的 UI 回退到原始结果内容），也没有 `search` 调用视图——发现型调用的 pending 状态保持为 generic 卡片，因为匹配只在 `execute` 之后才存在。（tool-fs-search 的 `grep`/`glob`。）
 
 硬性规则（违反会出问题）：