docs: rebalance prose cleanup and add trimming skill

packages/fs/tool-fs/src/session-cwd.ts

@@ -3,6 +3,8 @@
  * agent's per-session workspace (`exec.agent.session.header.cwd`), so each ACP session's
  * `read`/`write`/`edit` act on ITS workspace, not the server's launch dir — mirroring how
  * `dsh-tool-bash` defaults a bash `workdir` to the session cwd.
+ * Non-agent calls return `undefined`, leaving the fallback in the provider rather than reading
+ * `process.cwd()` at the tool seam.
  * @module @deepseek-ai/dsh-tool-fs/session-cwd
  */