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/lib/pty-run.js

@@ -216,8 +216,14 @@ function spawnRun(args) {
     });
   };
 
+  // Every pane the dashboard starts carries its lane id. A `ccam stage` call
+  // from inside it then resolves the lane exactly, instead of matching on cwd —
+  // which is ambiguous now that one directory can back both a `claude` lane and
+  // a `codex` lane (see bin/ccam.js's resolveLaneArg).
+  const env = { CCAM_LANE_ID: String(laneId) };
+
   if (!tmux.hasSession(id)) {
-    tmux.newSession({ name: id, cwd, argv });
+    tmux.newSession({ name: id, cwd, argv, env });
     record();
   } else if (SHELL_COMMANDS.has(tmux.paneCommand(id) || "")) {
     // The session exists but its pane is sitting at a bare shell prompt — a
@@ -226,7 +232,7 @@ function spawnRun(args) {
     // `--resume` and an initial prompt would never be typed, while the API
     // still answered 200. Run the argv in the pane the user already sees
     // instead of erroring or opening a second session.
-    tmux.sendCommand(id, argv);
+    tmux.sendCommand(id, argv, env);
     record();
   }
   // Pane is running something (a live `claude`, an editor, a build): adopt