fix(lanes): render undeclared lanes at their detected stage, quiet tmux polling noise

A lane whose sessions never call `ccam stage` had no declaration at all, so
its pipeline map stayed 100% pending even though detection was tracking real
progress. inferredDisplayStage renders such a lane AT its last detection
instead (display only — the DB's declared `stage` and detection-as-evidence
rules are untouched). Also stops tmux's own "no session" stderr noise from
spamming the journal on every poll.

server/__tests__/lanes-lib.test.js

@@ -589,12 +589,12 @@ describe("stage detection", () => {
       !payload.pipeline_nodes.some((n) => n.state === "done"),
       "inference must never render a node done — only a declared stage carrying evidence may"
     );
-    // lane.stage is still the default "idle", which is not itself a pipeline
-    // node/alias, so nodeStates() (unaware of detection) reports "pending" for
-    // every node here — detection only ever adds the `detected` flag alongside
-    // whatever nodeStates() already computed from the declared stage.
+    // lane.stage is still the default "idle" and `stages` is empty, so the lane
+    // has no declaration of its own to render and is displayed AT its detected
+    // node instead (inferredDisplayStage) — `current`, and flagged `detected`
+    // so it paints amber rather than as a declaration.
     const review = payload.pipeline_nodes.find((n) => n.id === "review");
-    assert.equal(review.state, "pending");
+    assert.equal(review.state, "current");
     assert.equal(review.detected, true);
     const implement = payload.pipeline_nodes.find((n) => n.id === "implement");
     assert.equal(implement.detected, true);
@@ -948,9 +948,10 @@ describe("stage detection", () => {
     }
   });
 
-  it("a stale detection stops rendering as `detected` in pipeline_nodes, even though the DB row still holds it", () => {
+  it("a stale detection stops rendering as `detected` on a lane that HAS declared a stage", () => {
     const { db } = require("../db");
     const l = lanes.createLane({ cwd: "/tmp/wt-detect-stale-render" });
+    lanes.setStage(l.id, { stage: "plan" });
     lanes.recordDetection(l.id, { nodeId: "tests" });
     const oldTime = new Date(Date.now() - 2 * 60 * 60 * 1000).toISOString();
     db.prepare("UPDATE lanes SET detected_at = ? WHERE id = ?").run(oldTime, l.id);
@@ -965,6 +966,29 @@ describe("stage detection", () => {
       !nodes.some((n) => n.detected),
       "a detection older than the TTL must not paint any node amber — it is no longer current information"
     );
+    // The declaration is what the lane still renders from.
+    assert.equal(nodes.find((n) => n.id === "plan").state, "current");
+    lanes.deleteLane(l.id);
+  });
+
+  it("a lane that never declared a stage keeps rendering its LAST detection, TTL or not", () => {
+    const { db } = require("../db");
+    const l = lanes.createLane({ cwd: "/tmp/wt-detect-undeclared-render" });
+    lanes.recordDetection(l.id, { nodeId: "tests" });
+    const oldTime = new Date(Date.now() - 2 * 60 * 60 * 1000).toISOString();
+    db.prepare("UPDATE lanes SET detected_at = ? WHERE id = ?").run(oldTime, l.id);
+
+    // With nothing declared, the last detection IS the lane's last known
+    // progress — blanking it left every non-CCAM repo's card 100% pending
+    // forever. Still amber (`detected`), still never `done`.
+    const payload = lanes.lanePayload(lanes.getLane(l.id));
+    const tests = payload.pipeline_nodes.find((n) => n.id === "tests");
+    assert.equal(tests.state, "current");
+    assert.equal(tests.detected, true);
+    assert.ok(!payload.pipeline_nodes.some((n) => n.state === "done"));
+    assert.ok(payload.progress > 0, "an inferred stage advances the progress bar");
+    // The declared stage the DB holds is reported untouched.
+    assert.equal(payload.stage, "idle");
     lanes.deleteLane(l.id);
   });
 });