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).

client/src/components/run/__tests__/LaneConsolePane.test.tsx

@@ -212,6 +212,16 @@ describe("LaneConsolePane", () => {
     await waitFor(() => expect(prompt.value).toBe("/ccam:ship-feature-lane add a button"));
   });
 
+  it("never pre-fills a claude slash command into a codex pane", async () => {
+    // pipeline_skill is a Claude Code slash command. Codex would take it as
+    // literal prose and run nothing, which is how a codex lane sits for half an
+    // hour with an untouched pipeline map.
+    const lane = { ...LANE, tool: "codex" as const, pipeline_skill: "/ccam:ship-feature-lane" };
+    render(<LaneConsolePane {...baseProps()} lanes={[lane]} />);
+    const prompt = screen.getByPlaceholderText(/ask claude/i) as HTMLTextAreaElement;
+    await waitFor(() => expect(prompt.value).toBe(""));
+  });
+
   it("renders an empty placeholder with selector when laneId is null but showLaneSelector is true (split-view)", () => {
     render(<LaneConsolePane {...baseProps()} laneId={null} showLaneSelector={true} />);
     expect(screen.getByTestId("pane-empty")).toBeInTheDocument();