docs: add running field to get_agent_meta, document stopped-container display (follow-up to #433)

docs/turn-loop.md

@@ -227,12 +227,17 @@ it as a stdio child via `--mcp-config`. The hyperhive socket name is
   `{state_dir}/hyperhive-status`; survives harness restarts. Pass
   an empty string to clear.
 - `get_agent_meta(name?)` — fetch identity + status metadata for
-  an agent: `{ name, role, hyperhive_rev, status_text,
+  an agent: `{ name, role, hyperhive_rev, running, status_text,
   status_set_at }`. Pass `name` to query a peer (e.g. check
   whether a sub-agent is idle before sending it work). Omit
   `name` to get your own identity stamp — replaces the previous
-  `whoami` tool. Status fields are `None` when the target has
-  never called `set_status` or has cleared it.
+  `whoami` tool. `running` is `true` when the container is up.
+  When `running` is `false` the host clears live-only sentinel
+  fields (`status_text`, `status_set_at`, `needs_login`,
+  `rate_limited`, `ctx_tokens`) before serving the response, so
+  stale on-disk state never reaches the caller. Status fields are
+  also `None` when the target has never called `set_status` or
+  has cleared it.
 - `request_next_turn()` — ask the harness to start another turn
   immediately after this one ends, even if the inbox is empty. Use for
   multi-turn tasks (long builds, sequential steps) where you want to