refactor(fs-search): apply #1119 review fixes to the packaged-rg spawn

- delete the singleQuote shell-quoting helper and its bash-spawning tests
  (no in-repo consumers; no shell layer exists anymore)
- drop spill from both collect streams: the tool never reads a raw spill
  path, and a lossy stdout read is a pure SEARCH_RAW_OUTPUT_OVERFLOW error
- prepend --no-config so a host RIPGREP_CONFIG_PATH cannot inject a --pre
  preprocessor into the unconfined spawn
- promote graceMs and stderrMaxBytes to validated Config fields (defaults
  SEARCH_GRACE_MS / SEARCH_STDERR_MAX_BYTES) instead of inheriting
  bash-local's config
- correct the grep tool's JSDoc seam reference (bash -> subprocess)
- drop the dead exit-127/command-not-found classification branch

docs/config-catalog.md

@@ -1733,12 +1733,16 @@ export interface Config {
   searchMetaMaxBytes?: number
   /** Max complete raw `rg` stdout bytes a search will parse; larger raw output fails with `SEARCH_RAW_OUTPUT_OVERFLOW`. */
   rawOutputMaxBytes?: number
+  /** Terminate-escalation grace period (ms) for one search process, handed to the subprocess seam. */
+  graceMs?: number
+  /** Max bytes retained for one search's stderr diagnostic tail (never surfaced to the model). */
+  stderrMaxBytes?: number
   /** Cooperative tool-call timeout budget (ms) on both tools, enforced by `@deepseek-ai/dsh-timeout-policy` through `exec.signal`. */
   timeoutMs?: number
 }
 ```
 
-Source: [`packages/fs/tool-fs-search/src/index.ts:70`](../packages/fs/tool-fs-search/src/index.ts)
+Source: [`packages/fs/tool-fs-search/src/index.ts:71`](../packages/fs/tool-fs-search/src/index.ts)
 
 ## `@deepseek-ai/dsh-tool-goal`