feat(lanes): give every pipeline node its own driver command

A pipeline template named ONE command for the whole run (`skill`), so the
only way to know what actually moves a given node was to read that node's
`detect` regexes. Each node now carries its own `command`: a slash command
(`/superpowers:writing-plans`) or a shell one (`ccam lanes hook ci-gate`),
whichever its detect rules already watch for.

The values are derived from each node's own detect rules, not invented —
every `ccam …` string was checked against bin/ccam.js and every
`/superpowers:*` against the installed plugin. Nodes reaching which is a
declaration rather than an action (`done`, `merged`, `reported`,
`e2e-feature-passed`, `qc-plan`) are deliberately left empty.

`pipelines.js` normalizes a missing or non-string value to "", so a
custom template written before this field keeps loading rather than
rendering "undefined". `nodeStates()` and GET /api/lanes/pipeline-stats
pass it through. Never executed by the dashboard — display text, the same
contract `skill` already had.

Surfaced where each view has room for it: the Workflows pass-rate panel
shows it under the node label and copies it on click; PipelineMap folds
it into the node tooltip, because a 16-node pipeline has to fit across
one card and there is no width for a second line.

`command?: string` is optional in the client type only to spare four
unrelated test fixtures — the server always sends the key, and the UI has
to branch on the empty string regardless.

Verified: npm run test:server (1373, +3), npm run test:client (459, +2),
tsc --noEmit, prettier and check-headers clean. docs/LANES.md § Custom
template format documents the field. openapi.yaml needs no change: the
lane payload and pipeline-stats were never schematized there.

server/__tests__/lanes-lib.test.js

@@ -126,6 +126,72 @@ describe("pipelines", () => {
 const lanes = require("../lib/lanes");
 const features = require("../lib/lane-features");
 
+describe("per-node driver command", () => {
+  it("gives every built-in template's nodes a command field, and carries it into the render states", () => {
+    for (const pipeline of listPipelines()) {
+      for (const node of pipeline.nodes) {
+        assert.equal(
+          typeof node.command,
+          "string",
+          `${pipeline.id}/${node.id} must declare a command string`
+        );
+      }
+      const states = nodeStates(pipeline, { stage: pipeline.nodes[0].id, stages: {} });
+      assert.deepEqual(
+        states.map((n) => n.command),
+        pipeline.nodes.map((n) => n.command),
+        `${pipeline.id}: nodeStates must pass each node's command through`
+      );
+    }
+  });
+
+  it("names a real driver for the stages an agent actually drives", () => {
+    const ship = getPipeline("ship-feature");
+    const byId = Object.fromEntries(ship.nodes.map((n) => [n.id, n.command]));
+
+    assert.equal(byId.intake, "/superpowers:brainstorming");
+    assert.equal(byId.implementing, "/superpowers:test-driven-development");
+    assert.equal(byId.gates, "ccam lanes hook ci-gate");
+    // A terminal node has no driver of its own: reaching `done` is a
+    // declaration, not something a command performs.
+    assert.equal(byId.done, "");
+  });
+
+  it("defaults a template node that declares no command to the empty string", () => {
+    // A custom template written before this field existed must keep loading -
+    // an undefined command would render as "undefined" in the UI.
+    const fs = require("node:fs");
+    const dir = fs.mkdtempSync(pathMod.join(os.tmpdir(), "pipelines-nocmd-"));
+    fs.writeFileSync(
+      pathMod.join(dir, "legacy.json"),
+      JSON.stringify({
+        id: "legacy-nocmd",
+        name: "Legacy",
+        nodes: [
+          { id: "start", label: "Start" },
+          { id: "done", command: 42 },
+        ],
+      })
+    );
+    const prev = process.env.DASHBOARD_PIPELINES_DIR;
+    process.env.DASHBOARD_PIPELINES_DIR = dir;
+    const { reload } = require("../lib/pipelines");
+    reload();
+    try {
+      const p = getPipeline("legacy-nocmd");
+      assert.deepEqual(
+        p.nodes.map((n) => n.command),
+        ["", ""],
+        "a missing or non-string command must normalize to empty, never leak through"
+      );
+    } finally {
+      if (prev === undefined) delete process.env.DASHBOARD_PIPELINES_DIR;
+      else process.env.DASHBOARD_PIPELINES_DIR = prev;
+      reload();
+    }
+  });
+});
+
 describe("lanes lib", () => {
   it("creates, lists, updates and deletes a lane", () => {
     const l = lanes.createLane({ title: "Feature A", cwd: "/tmp/wt/a", branch: "feat/a" });