chore: v2.8.13 — Artifacts reinstall/edit/installs, agent steps in chat, pick a local file to attach, Windows paths as links

- Chat: an Agent step shows its task, status and tool calls and opens its conversation in place; Windows paths (E:\…, C:/…) in replies open as files
- Prompt: attach a file on this computer by path (native picker), clearer too-large messages
- Artifacts: edit title/description and a skill's files (new snapshot), Reinstall, install history, Hub-only rows, skills installed into ~/.claude/skills and ~/.agents/skills
- Files: batch upload of small files in one extract
- AI Tools: npm install falls back to --prefix ~/.local when the global prefix is not writable

server/routes/homes.js

@@ -7,6 +7,7 @@
  *   GET  /api/homes/trash                every Trash the caller may open, merged
  *   GET  /api/homes/:who/fs/list|trash|zip|download
  *   POST /api/homes/:who/fs/mkdir|newfile|rename|move|copy|delete|upload|trash/restore|trash/purge
+ *   POST /api/homes/:who/fs/upload-batch|upload-check   many small files in one request
  *
  * `:who` is `me`, or — for an admin — another user's name: read-only
  * (`403 EREADONLY` on every write) and written to the audit log. The one
@@ -36,6 +37,7 @@ function fail(res, err) {
       ENOHOME: 404,
       EBADPATH: 400,
       EBADNAME: 400,
+      EBADBODY: 400,
       ENOFILE: 404,
       ESECRET: 403,
       EFOREIGN: 403,
@@ -314,5 +316,38 @@ router.post(
     }
   }, W)
 );
+router.post(
+  "/:who/fs/upload-batch",
+  sameOriginGuard,
+  handle(async (req, res, home) => {
+    try {
+      const out = await fx.uploadBatch(
+        home.dir,
+        typeof req.query.dir === "string" ? req.query.dir : "",
+        req,
+        { conflict: req.query.conflict, trash: trashFor(req, home) }
+      );
+      res.status(201).json(out);
+    } catch (err) {
+      req.resume();
+      throw err;
+    }
+  }, W)
+);
+router.post(
+  "/:who/fs/upload-check",
+  sameOriginGuard,
+  handle(
+    async (req, res, home) =>
+      res.json(
+        await fx.uploadCheck(
+          home.dir,
+          typeof req.body?.dir === "string" ? req.body.dir : "",
+          req.body?.paths
+        )
+      ),
+    W
+  )
+);
 
 module.exports = router;