feat(lanes): extract skills-install lib, add POST /api/skills/install (F4)

bin/ccam.js

@@ -1529,16 +1529,16 @@ async function cmdLanesAdd(args) {
  * existing global copy with the current one.
  */
 function cmdSkillsInstall() {
-  const src = path.join(REPO_ROOT, ".claude", "skills", "ship-feature-lane");
-  if (!fs.existsSync(src)) {
-    console.error(`✖ not found: ${src}`);
+  const { installShipFeatureLaneSkill } = require(
+    path.join(REPO_ROOT, "server", "lib", "skills-install.js")
+  );
+  try {
+    const result = installShipFeatureLaneSkill({ repoRoot: REPO_ROOT });
+    console.log(`${c.green("✔")} installed ship-feature-lane skill -> ${result.path}`);
+  } catch (err) {
+    console.error(`✖ ${err.message}`);
     process.exitCode = 1;
-    return;
   }
-  const dest = path.join(require("node:os").homedir(), ".claude", "skills", "ship-feature-lane");
-  fs.mkdirSync(path.dirname(dest), { recursive: true });
-  fs.cpSync(src, dest, { recursive: true, force: true });
-  console.log(`${c.green("✔")} installed ship-feature-lane skill -> ${dest}`);
 }
 
 /**

server/index.js

@@ -67,6 +67,7 @@ const remoteSourcesRouter = require("./routes/remote-sources");
 const metricsRouter = require("./routes/metrics");
 const lanesRouter = require("./routes/lanes");
 const locksRouter = require("./routes/locks");
+const skillsRouter = require("./routes/skills");
 
 const APP_VERSION = (() => {
   try {
@@ -107,6 +108,7 @@ function createApp() {
   app.use("/api/webhooks", webhooksRouter);
   app.use("/api/remote-sources", remoteSourcesRouter);
   app.use("/api/metrics", metricsRouter);
+  app.use("/api/skills", skillsRouter);
   app.get("/api/openapi.json", (_req, res) => {
     res.json(openApiSpec);
   });

server/lib/skills-install.js

@@ -0,0 +1,32 @@
+/**
+ * @file Installs .claude/skills/ship-feature-lane/ into ~/.claude/skills/, so
+ * /ship-feature-lane is discoverable from a session running inside any
+ * lane's own working directory — not just inside this repo, where it lives
+ * until installed. Shared by bin/ccam.js's `ccam skills install` CLI and the
+ * POST /api/skills/install route, so there is exactly one copy of this
+ * logic. Pure filesystem action.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+const fs = require("node:fs");
+const os = require("node:os");
+const path = require("node:path");
+
+/**
+ * @param {{repoRoot: string}} options - `repoRoot` is this checkout's own
+ *   root (bin/ccam.js already computes this as `REPO_ROOT`; the server
+ *   computes its own equivalent — see the route for how).
+ * @returns {{installed: true, path: string}}
+ */
+function installShipFeatureLaneSkill({ repoRoot }) {
+  const src = path.join(repoRoot, ".claude", "skills", "ship-feature-lane");
+  if (!fs.existsSync(src)) {
+    throw Object.assign(new Error(`not found: ${src}`), { code: "ENOSKILLSRC" });
+  }
+  const dest = path.join(os.homedir(), ".claude", "skills", "ship-feature-lane");
+  fs.mkdirSync(path.dirname(dest), { recursive: true });
+  fs.cpSync(src, dest, { recursive: true, force: true });
+  return { installed: true, path: dest };
+}
+
+module.exports = { installShipFeatureLaneSkill };

server/routes/skills.js

@@ -0,0 +1,28 @@
+/**
+ * @file Machine-wide (not lane-scoped) skill installation.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+const { Router } = require("express");
+const path = require("node:path");
+const { installShipFeatureLaneSkill } = require("../lib/skills-install");
+const { sameOriginGuard } = require("./run");
+
+const router = Router();
+
+/** This server's own checkout root — server/routes/skills.js is two levels
+ *  under it (server/routes/), same computation bin/ccam.js's REPO_ROOT
+ *  already does from its own location. */
+const REPO_ROOT = path.resolve(__dirname, "..", "..");
+
+router.post("/install", sameOriginGuard, (req, res) => {
+  try {
+    res.json(installShipFeatureLaneSkill({ repoRoot: REPO_ROOT }));
+  } catch (err) {
+    if (err.code === "ENOSKILLSRC") {
+      return res.status(400).json({ error: { code: err.code, message: err.message } });
+    }
+    res.status(500).json({ error: { code: err.code || "ERUNTIME", message: err.message } });
+  }
+});
+
+module.exports = router;