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/tmux.js

@@ -34,12 +34,24 @@ function hasSession(name) {
   }
 }
 
+/** `-e NAME=value` pairs for tmux, in a stable order. */
+function envFlags(env) {
+  const flags = [];
+  for (const [key, value] of Object.entries(env || {})) flags.push("-e", `${key}=${value}`);
+  return flags;
+}
+
 /**
  * Create a detached tmux session running `argv` as the pane's command. Throws
  * if tmux itself fails to start (caller decides how to surface that).
+ *
+ * `env` becomes tmux `-e NAME=value` pairs, which tmux puts in the pane's own
+ * environment (tmux >= 3.2). The dashboard uses it for CCAM_LANE_ID so a `ccam`
+ * call from inside the pane knows exactly which lane it belongs to instead of
+ * guessing from cwd — see resolveLaneArg in bin/ccam.js.
  */
-function newSession({ name, cwd, argv }) {
-  execImpl(["new-session", "-d", "-s", name, "-c", cwd, "--", ...argv]);
+function newSession({ name, cwd, argv, env }) {
+  execImpl(["new-session", "-d", "-s", name, "-c", cwd, ...envFlags(env), "--", ...argv]);
   enableMouse(name);
 }
 
@@ -78,9 +90,17 @@ function shellQuote(arg) {
  * Type `argv` into an existing session's pane and press Enter. Only ever
  * called when the pane sits at a shell prompt (see `paneCommand`); `-l` sends
  * the string literally so no character is read as a tmux key name.
+ *
+ * `env` rides along as a shell assignment prefix on the SAME line — tmux's own
+ * `-e` applies only at session creation, and a shell that is already running
+ * takes its environment from the command line. The name is never quoted (bash
+ * only recognizes an assignment when the `=` is unquoted); the value is.
  */
-function sendCommand(name, argv) {
-  execImpl(["send-keys", "-t", name, "-l", argv.map(shellQuote).join(" ")]);
+function sendCommand(name, argv, env) {
+  const prefix = Object.entries(env || {})
+    .map(([key, value]) => `${key}=${shellQuote(value)} `)
+    .join("");
+  execImpl(["send-keys", "-t", name, "-l", prefix + argv.map(shellQuote).join(" ")]);
   execImpl(["send-keys", "-t", name, "Enter"]);
 }