fix(runs): persist tmux-backed runs so a resumed session shows its own info

`dashboard_runs.mode` is NOT NULL and `recordRun` swallows insert errors by
design, so pty-run.js passing `mode: null` meant NO tmux-backed run was ever
persisted — the newest row in a live database dated from before pty-run.js
replaced run-spawner.js. `publicRun` reads cwd, model, prompt preview,
started_at and session_id off that row and the handle itself is recomputed
from tmux, so the runs modal rendered a live row with no cwd, no model, no
prompt and a start date of Jan 1 1970. The same missing row is why a resumed
session kept its separate `external` badge: the client dedupes an external
session against the session ids carried by run rows, and no run row ever
carried one.

- pty-run.js records `mode: "interactive"` — every run here is one pane.
- dashboard-runs.js still never fails a live run on a db error, but warns
  instead of swallowing silently; that silence hid this for six weeks.
- RunHistory renders `startedAt: 0` as "-" rather than dating a row with no
  known start time to the epoch.

Also closes the other half of the same lie: adopting a pane that is already
running an agent now throws ERUNLIVE (409 from both the lane start action and
POST /api/run) when the request carried a prompt or a resumeSessionId. That
argv cannot be typed over a live agent, so answering 200 reported a resume
that never spawned. A start asking for nothing but a pane still adopts.

server/README.md

@@ -555,7 +555,12 @@ failures return `500` with `error.stderr`.
 
 `start` returns `409 ERUNLIVE` when the lane's recorded run is still `spawning`
 or `running`: overwriting `run_id` would orphan that child, and a later `reset`
-would then `git clean -fd` a directory the orphan is still writing into.
+would then `git clean -fd` a directory the orphan is still writing into. It
+returns the same code when the lane's tmux pane is running an agent and the
+request carried a `prompt` or `resumeSessionId` — `pty-run.js` will not type
+over a live agent, and adopting the pane silently would answer 200 for a resume
+that never spawned. `POST /api/run` maps that code to `409` too; a start with
+neither field still adopts the pane.
 
 Besides the stage a skill declares explicitly, every lane also carries a
 server-inferred `detected_stage`: `server/lib/stage-detect.js` matches each

server/__tests__/pty-run.test.js

@@ -335,4 +335,91 @@ describe("pty-run", () => {
     );
     assert.ok(!call.some((a) => String(a).startsWith("--dangerously-bypass")));
   });
+
+  // `dashboard_runs.mode` is NOT NULL and recordRun swallows insert errors, so a
+  // null there persisted nothing at all while every call still looked fine: the
+  // runs modal rendered a row with no cwd, model, prompt or start time, and a
+  // resumed session kept its separate `external` row because no run row ever
+  // carried its session id. These assert the row actually lands.
+  it("refuses to swallow a resume or a prompt when the pane already runs an agent", () => {
+    // Adopting silently here answered 200 while spawning no `--resume` at all:
+    // the dashboard reported a resumed session that never happened.
+    tmux.__setExecImpl((args) => {
+      if (args[0] === "display-message") return "claude\n";
+      return ""; // has-session succeeds → pane is busy with a live agent
+    });
+    assert.throws(
+      () => pty.spawnRun({ laneId: 51, cwd: "/tmp/repo", resumeSessionId: "abc12345" }),
+      (err) => err.code === "ERUNLIVE"
+    );
+    assert.throws(
+      () => pty.spawnRun({ laneId: 51, cwd: "/tmp/repo", initialPrompt: "do the thing" }),
+      (err) => err.code === "ERUNLIVE"
+    );
+  });
+
+  it("still adopts a busy pane when the request asked for nothing but a pane", () => {
+    const calls = [];
+    tmux.__setExecImpl((args) => {
+      calls.push(args);
+      if (args[0] === "display-message") return "claude\n";
+      return "";
+    });
+    const handle = pty.spawnRun({ laneId: 52, cwd: "/tmp/repo" });
+    assert.equal(handle.id, "agenthub-lane-52");
+    assert.ok(!calls.some((c) => c[0] === "new-session"));
+    assert.ok(!calls.some((c) => c[0] === "send-keys"));
+  });
+
+  describe("run persistence", () => {
+    const dashboardRuns = require("../lib/dashboard-runs");
+
+    it("spawnRun persists the run so the runs list has cwd, model and prompt", () => {
+      tmux.__setExecImpl((args) => {
+        if (args[0] === "has-session") {
+          const e = new Error("gone");
+          e.status = 1;
+          throw e;
+        }
+        return "";
+      });
+      pty.spawnRun({
+        laneId: 71,
+        cwd: "/tmp/persisted",
+        model: "claude-opus-5",
+        initialPrompt: "ship it",
+      });
+
+      const row = dashboardRuns.getRun("agenthub-lane-71");
+      assert.ok(row, "expected a dashboard_runs row for the spawned run");
+      assert.equal(row.cwd, "/tmp/persisted");
+      assert.equal(row.model, "claude-opus-5");
+      assert.equal(row.prompt_preview, "ship it");
+      assert.equal(row.lane_id, 71);
+      assert.ok(row.started_at, "started_at must be set, or the UI dates the row to the epoch");
+      assert.ok(row.mode, "mode is NOT NULL — a null here silently drops the whole insert");
+    });
+
+    it("a resumed run carries the session id, which is what dedupes the external row", () => {
+      tmux.__setExecImpl((args) => {
+        if (args[0] === "has-session") {
+          const e = new Error("gone");
+          e.status = 1;
+          throw e;
+        }
+        return "";
+      });
+      const sessionId = "c2055094-09cf-4735-9712-09e5cdf7023f";
+      const handle = pty.spawnRun({
+        laneId: 72,
+        cwd: "/tmp/resumed",
+        resumeSessionId: sessionId,
+      });
+
+      // The UI reads sessionId off the run list; an external session whose id is
+      // already on a run row is not repeated as its own `external` row.
+      assert.equal(handle.sessionId, sessionId);
+      assert.equal(dashboardRuns.getRun("agenthub-lane-72").resume_session_id, sessionId);
+    });
+  });
 });

server/lib/dashboard-runs.js

@@ -91,8 +91,12 @@ function recordRun(handle) {
       lane_id: typeof handle.laneId === "number" ? handle.laneId : null,
       tool: handle.tool === "codex" ? "codex" : "claude",
     });
-  } catch {
-    /* persistence is best-effort */
+  } catch (err) {
+    // Best-effort by design (a live run must never fail because sqlite did),
+    // but not silent: a swallowed insert leaves the runs modal showing rows with
+    // no cwd, model, prompt or start time, which reads as a UI bug rather than a
+    // persistence one. Say it once, here, where the cause is known.
+    console.warn(`[dashboard-runs] failed to record run ${handle?.id}: ${err.message}`);
   }
 }
 

server/lib/pty-run.js

@@ -200,7 +200,13 @@ function spawnRun(args) {
     dashboardRuns.recordRun({
       id,
       sessionId: resumeSessionId || null,
-      mode: null,
+      // `dashboard_runs.mode` is NOT NULL. Passing null made every insert throw
+      // inside recordRun's best-effort catch, so no tmux-backed run was ever
+      // persisted: publicRun then read its cwd/model/prompt/startedAt off a row
+      // that did not exist (a blank row dated Jan 1 1970 in the runs modal), and
+      // session_id never landed either, so a resumed session stayed listed as a
+      // separate `external` row. Every run here is one interactive pane.
+      mode: "interactive",
       cwd,
       tool: tool === "codex" ? "codex" : "claude",
       model: model || null,
@@ -238,6 +244,18 @@ function spawnRun(args) {
   // Pane is running something (a live `claude`, an editor, a build): adopt
   // silently, same convention as this repo's server port-adoption logic — no
   // error, no duplicate session. Attaching shows the user what is running.
+  //
+  // Adopting is only honest when the request asked for nothing more than a
+  // pane. A Resume or an initial prompt cannot be delivered into a pane that is
+  // already running an agent (typing over it is what the shell-pane branch
+  // above exists to avoid), so answering 200 there reports work that never
+  // happened: the user sees "resumed" while no `--resume` was ever spawned.
+  else if (resumeSessionId || initialPrompt) {
+    throw makeErr(
+      "ERUNLIVE",
+      `lane ${laneId}'s pane is already running \`${tmux.paneCommand(id) || "a process"}\` — stop it before resuming a session or sending a prompt`
+    );
+  }
 
   return getRun(id);
 }

server/routes/lanes.js

@@ -898,7 +898,9 @@ function sendLifecycleError(res, err) {
   if (["ENOTMANAGED", "EOUTSIDEROOT", "ENOTWORKTREE", "EEXPECT"].includes(err.code)) {
     return res.status(400).json({ error: { code: err.code, message: err.message } });
   }
-  if (["ESTALE", "EUNPUSHED"].includes(err.code)) {
+  // ERUNLIVE: the lane's pane is busy with a live agent, so a resume/prompt
+  // could not be delivered — a conflict, not a bad request or a server fault.
+  if (["ESTALE", "EUNPUSHED", "ERUNLIVE"].includes(err.code)) {
     return res.status(409).json({
       error: {
         code: err.code,

server/routes/run.js

@@ -256,6 +256,10 @@ router.post("/", (req, res) => {
     });
     return res.status(201).json(handle);
   } catch (err) {
+    // A busy pane is a conflict with live state, not a malformed request.
+    if (err.code === "ERUNLIVE") {
+      return res.status(409).json({ error: { code: err.code, message: err.message } });
+    }
     if (err.code && err.code.startsWith("E")) {
       return res.status(400).json({ error: { code: err.code, message: err.message } });
     }