fix(lanes): auto-detect and report stage for codex lanes (issue 11)

A lane on the 16-node `ship-feature` template showed an untouched pipeline
map and never declared a stage. Four independent causes, fixed at their
shared choke points:

1. Codex emits no hooks, so `touchLaneFromHook` — the only caller of
   `stage-detect.detect()`, and correctly pinned to `claude` — could never
   see a `codex` lane. New `server/lib/codex-ingest.js` tails Codex's own
   rollout journals (`$CODEX_HOME/sessions/**/rollout-*.jsonl`), maps its
   tool calls onto the hook-shaped `{tool_name, tool_input}` the matcher
   already understands, and feeds the existing detect path plus an
   idle/running status mirror under the same guard hooks use. Polled every
   `DASHBOARD_CODEX_POLL_MS` ms (default 15000, `0` disables).
2. `resolveLaneArg` matched on cwd alone, so with a claude and a codex lane
   at one directory (the composite `idx_lanes_cwd_tool`) a `ccam stage`
   call could drive the sibling lane's card. It now resolves by
   `--lane` → `CCAM_LANE_ID` → `--tool`/harness marker → owning lane, and
   errors naming both candidates rather than picking one. Every pane the
   dashboard starts carries `CCAM_LANE_ID` (`tmux new-session -e`, or an
   assignment prefix when typing into a live shell pane).
3. `recordDetection`'s declared-wins veto had no exit: a lane left at the
   pipeline's last node rejected every detection for the rest of its life.
   A declaration on the LAST node no longer vetoes — the pipeline is over
   there, so a later detection is new work. Nothing else is relaxed, and
   detection still never writes `stage` nor renders `done`.
4. The run console pre-filled the pipeline's Claude slash command into
   codex panes, which Codex reads as prose — so the skill that would have
   called `ccam stage` never ran. Claude lanes only now.

A codex lane's *declared* stage still depends on the session calling
`ccam stage`; `AGENTS.md` is the only lever CCAM has, so it now says so.

Verified: server 1345/1345, client 441/441, and end-to-end against a real
codex lane row (detected_stage/detected_signal set, declared stage
untouched, no node rendered done).

server/README.md

@@ -566,9 +566,19 @@ server-inferred `detected_stage`: `server/lib/stage-detect.js` matches each
 hook event's tool name/input against the pipeline template's per-node
 `detect` rules, and `server/routes/hooks.js`'s `touchLaneFromHook` calls it on
 every hook before any other lane bookkeeping. It is forward-only, yields to a
-declared stage that is already ahead, and — the one rule that matters —
-never counts as evidence and never renders a node as `done` (see
-`docs/LANES.md#stage-detection`).
+declared stage that is already ahead — unless that declaration is the
+pipeline's last node, where the pipeline is finished and a later detection is
+new work — and, the one rule that matters, never counts as evidence and never
+renders a node as `done` (see `docs/LANES.md#stage-detection`).
+
+A `codex` lane has no hooks to read, so `server/lib/codex-ingest.js` feeds the
+same matcher from Codex's own rollout journals under
+`$CODEX_HOME/sessions/**/rollout-*.jsonl`, polled every
+`DASHBOARD_CODEX_POLL_MS` ms (default 15000, `0` disables) and mapping Codex's
+tool calls onto the `{tool_name, tool_input}` shape a hook delivers. The same
+pass mirrors that lane's `status` between `idle` and `running` from the
+journal's mtime, under the guard hook ingestion uses (no `run_id`, only from
+`idle`/`running`); it writes nothing else.
 
 ### Remote Data Sources