Add minimal stock listing app: actions, Postgres schema, stocks page, Claude Agent SDK harness

- Add stocks table (server/db) with list/get/add/update/delete actions, scoped
  per user, backing both the chat agent and the /stocks UI via
  useActionQuery/useActionMutation
- Add mobile-first /stocks page (shadcn table/cards, watchlist, search) and
  wire it into the sidebar, navigation state, and view-screen context
- Install the platform's Claude Agent SDK harness (server/plugins,
  server/routes/api/claude-agent) so the app agent runs on the platform's own
  Claude subscription instead of the Builder.io gateway; fix the vendored
  turn.post.ts route to resolve the session and wrap it in
  runWithRequestContext, since custom /api/ routes aren't auto-wrapped in
  request context the way /_agent-native/actions/* are
- Add shadcn table/badge/dialog/select components (Tabler icons, not lucide)

AGENTS.md

@@ -43,10 +43,37 @@ workflow needs durable UI around the conversation.
 - For new features, update UI, actions, skills/instructions, and application
   state when applicable.
 
+## What This App Does
+
+A minimal stock listing app. Each user keeps a personal list of stock tickers
+(symbol, company name, exchange, sector, price, change percent, market cap,
+watchlisted) at the `/stocks` page. Chat remains the primary surface for
+asking the agent to add, look up, or edit listings; `/stocks` is the durable
+UI for browsing, searching, and managing the list at a glance.
+
+## Actions
+
+| Action         | Method | Description                                                             |
+| -------------- | ------ | ------------------------------------------------------------------------ |
+| `list-stocks`  | GET    | List the current user's stock listings. Supports `search`, `exchange`, `watchlistedOnly`. |
+| `get-stock`    | GET    | Get one listing by `id` or `symbol`.                                    |
+| `add-stock`    | POST   | Add a new listing (`symbol`, `companyName` required; fails if symbol already listed). |
+| `update-stock` | PUT    | Patch a listing by `id` — price, change percent, sector, `watchlisted` ("true"/"false"), etc. |
+| `delete-stock` | DELETE | Delete a listing by `id`.                                               |
+| `hello`        | GET    | Starter example action.                                                 |
+| `navigate`     | agent-only | Navigate the UI to a view/path (adds `view: "stocks"` for `/stocks`).|
+| `view-screen`  | agent-only | Read current navigation state; when the user is on `/stocks`, also returns the full stock listing snapshot. |
+
+Stocks are scoped per `ownerEmail` (the authenticated user). Data lives in
+the `stocks` table in Postgres (`DATABASE_URL`) in this deployment, or SQLite
+at `data/app.db` for local dev without a `DATABASE_URL` — see
+`server/db/schema.ts` and `server/plugins/db.ts`.
+
 ## Application State
 
 - `navigation` should describe the current view and selected entity ids. The
-  default chat view is `chat` at `/`.
+  default chat view is `chat` at `/`; the stock listing view is `stocks` at
+  `/stocks`.
 - `navigate` may be used to move the UI when the app supports it.
 - `view-screen` is the first tool to call when the user's visible context
   matters.