feat(scribe): snippet management UI + REST routes; embed snippets on create

Step 6 of the Drafter recall milestone (#227): a human-facing surface for
the reusable-code snippets that agents record via MCP, plus the REST API
behind it. Backend embeds snippets inline on create/update so they're
recallable immediately, not only after a restart.

Backend:
- routes/snippets.py: GET/POST /api/snippets, GET/PATCH/DELETE
  /api/snippets/<id>. Share-aware per rule #78 (get_note_for_user +
  can_write_note), writes performed as the owner; list owner-scoped —
  mirrors routes/notes.py. Registered in app.py.
- services/snippets.py: embed on create/update via a _embed_snippet
  fire-and-forget helper, covering BOTH the MCP tool and the REST route
  by construction. A snippet's value is immediate recall, so it can't wait
  for the startup-only backfill (see issue: MCP create path doesn't embed
  inline for notes/tasks generally).
- tests/test_routes_snippets.py: structural registration + handler/service
  contract + PATCH-field ↔ update_snippet-kwarg parity (rule #33).

Frontend (Vue 3 + TS):
- api/snippets.ts: typed client, modeled on api/systems.ts.
- views: SnippetListView (search, skeleton/empty/error states),
  SnippetDetailView (read + copy-to-clipboard, ConfirmDialog delete),
  SnippetEditorView (create/edit all fields, Ctrl/Cmd+S, Esc, autofocus,
  validation). v1 quality per rules #24/#27.
- router: /snippets, /snippets/new, /snippets/:id, /snippets/:id/edit.
- NoteType union widened to include 'snippet'; Snippets nav link added to
  AppHeader (desktop pill bar + mobile menu).
- Design system: Moss --color-action-primary for action buttons, accent
  --color-primary reserved for tags/brand (Hybrid rule); focus rings;
  JetBrains Mono for code/name/signature/location.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pa2EsuB54BuWQ8GfJq9c7t

src/scribe/routes/snippets.py

@@ -0,0 +1,137 @@
+"""REST routes for snippets — reusable functions/components recorded for recall.
+
+A snippet is a note with note_type='snippet' (see services/snippets.py). These
+routes feed the web management UI; the MCP tools (mcp/tools/snippets.py) are the
+agent-facing surface. Both go through services/snippets.py, so the
+serialize/parse contract and embedding-on-create live in one place (DRY).
+
+ACL (rule #78): reads/writes of a single snippet resolve through the share-aware
+`get_note_for_user` + `can_write_note`, and writes are performed as the OWNER so
+a shared editor isn't rejected by the owner-scoped service — mirroring
+routes/notes.py. The list is owner-scoped, matching the note-browse surface.
+"""
+import logging
+
+from quart import Blueprint, jsonify, request
+
+from scribe.auth import get_current_user_id, login_required
+from scribe.routes.utils import not_found, parse_pagination
+from scribe.services import snippets as snippets_svc
+from scribe.services.access import can_write_note
+from scribe.services.notes import get_note_for_user
+
+logger = logging.getLogger(__name__)
+
+snippets_bp = Blueprint("snippets", __name__, url_prefix="/api/snippets")
+
+# Fields the create/update payload may carry, mapped straight to the service.
+_STR_FIELDS = ("name", "code", "language", "signature", "when_to_use", "repo", "path", "symbol")
+
+
+async def _load_snippet(uid: int, snippet_id: int):
+    """Share-aware resolve of a snippet by id → (note, permission) or None if it
+    isn't accessible or isn't a snippet."""
+    result = await get_note_for_user(uid, snippet_id)
+    if result is None:
+        return None
+    note, permission = result
+    if note.note_type != snippets_svc.SNIPPET_NOTE_TYPE:
+        return None
+    return note, permission
+
+
+@snippets_bp.route("", methods=["GET"])
+@login_required
+async def list_snippets_route():
+    uid = get_current_user_id()
+    q = request.args.get("q") or None
+    tag = request.args.get("tag", "")
+    limit, offset = parse_pagination()
+    items, total = await snippets_svc.list_snippets(
+        uid, q=q, tag=tag, limit=limit, offset=offset,
+    )
+    return jsonify({"snippets": items, "total": total})
+
+
+@snippets_bp.route("", methods=["POST"])
+@login_required
+async def create_snippet_route():
+    uid = get_current_user_id()
+    data = await request.get_json() or {}
+    name = (data.get("name") or "").strip()
+    code = (data.get("code") or "").strip()
+    if not name or not code:
+        return jsonify({"error": "name and code are required"}), 400
+    project_id = data.get("project_id") or None
+    note = await snippets_svc.create_snippet(
+        uid,
+        name=name,
+        code=data.get("code", ""),
+        language=data.get("language", ""),
+        signature=data.get("signature", ""),
+        when_to_use=data.get("when_to_use", ""),
+        repo=data.get("repo", ""),
+        path=data.get("path", ""),
+        symbol=data.get("symbol", ""),
+        tags=data.get("tags"),
+        project_id=project_id,
+    )
+    return jsonify(snippets_svc.snippet_to_dict(note)), 201
+
+
+@snippets_bp.route("/<int:snippet_id>", methods=["GET"])
+@login_required
+async def get_snippet_route(snippet_id: int):
+    uid = get_current_user_id()
+    loaded = await _load_snippet(uid, snippet_id)
+    if loaded is None:
+        return not_found("Snippet")
+    note, permission = loaded
+    data = snippets_svc.snippet_to_dict(note)
+    data["permission"] = permission
+    return jsonify(data)
+
+
+@snippets_bp.route("/<int:snippet_id>", methods=["PATCH"])
+@login_required
+async def update_snippet_route(snippet_id: int):
+    uid = get_current_user_id()
+    loaded = await _load_snippet(uid, snippet_id)
+    if loaded is None:
+        return not_found("Snippet")
+    note, _ = loaded
+    if not await can_write_note(uid, snippet_id):
+        return jsonify({"error": "Permission denied"}), 403
+    owner_uid = note.user_id
+    data = await request.get_json() or {}
+
+    # Partial update: only keys present in the payload change (the service
+    # treats None as "leave unchanged"). Empty strings ARE applied — the form
+    # sends the full field set, so a cleared field is an intentional clear.
+    kwargs = {k: data[k] for k in _STR_FIELDS if k in data}
+    if "tags" in data:
+        kwargs["tags"] = data["tags"]
+    if "project_id" in data:
+        kwargs["project_id"] = data["project_id"] or None
+
+    updated = await snippets_svc.update_snippet(owner_uid, snippet_id, **kwargs)
+    if updated is None:
+        return not_found("Snippet")
+    return jsonify(snippets_svc.snippet_to_dict(updated))
+
+
+@snippets_bp.route("/<int:snippet_id>", methods=["DELETE"])
+@login_required
+async def delete_snippet_route(snippet_id: int):
+    uid = get_current_user_id()
+    loaded = await _load_snippet(uid, snippet_id)
+    if loaded is None:
+        return not_found("Snippet")
+    note, _ = loaded
+    if not await can_write_note(uid, snippet_id):
+        return jsonify({"error": "Permission denied"}), 403
+    from scribe.services.trash import delete as trash_delete
+    batch = await trash_delete(note.user_id, "note", snippet_id)
+    if batch is None:
+        return not_found("Snippet")
+    return "", 204