chore: standardize justfile commands across modules (#694)

- frontend: rename `dev` to `run` (keep `dev` as alias for compat)
- add `r` alias to backend and frontend (matches transcoder/moderation)
- add `just tunnel` command for ngrok
- update docs to reference `just frontend run`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.5 <[e-mail]>

AGENTS.md

···
 
 ## 💻 Development Commands
 *   **Backend:** `just backend run`
-*   **Frontend:** `just frontend dev`
+*   **Frontend:** `just frontend run`
 *   **Tests:** `just backend test` (run from repo root, not from backend/)
 *   **Linting:** `just backend lint` (Python) / `just frontend check` (Svelte)
 *   **Migrations:** `just backend migrate "message"` (create), `just backend migrate-up` (apply)

README.md

···
 just backend run
 
 # run frontend (hot reloads at http://localhost:5173)
-just frontend dev
+just frontend run
 ```
 
 ### useful commands

backend/justfile

···
 set shell := ["bash", "-eu", "-o", "pipefail", "-c"]
 default := "run"
 
+alias r := run
+
 # run backend server (hot reloads)
 run:
     uv run uvicorn backend.main:app --reload --host 0.0.0.0 --port ${PORT:-8001}

docs/README.md

···
 just backend run
 
 # frontend
-just frontend dev
+just frontend run
 
 # run tests
 just backend test

docs/deployment/environments.md

···
 DOCKET_URL=redis://localhost:6379 just backend run
 
 # terminal 3: start frontend
-just frontend dev
+just frontend run
 
 # optional: start transcoder
 just transcoder run

frontend/justfile

···
 set shell := ["bash", "-eu", "-o", "pipefail", "-c"]
-default := "dev"
+default := "run"
+
+alias r := run
+alias dev := run
 
 # run frontend dev server (hot reloads)
-dev:
-    cd {{justfile_directory()}}/frontend && bun run dev --host 0.0.0.0
+run:
+    bun run dev --host 0.0.0.0
 
 # check svelte types
 check:
-    cd {{justfile_directory()}}/frontend && bun run check
+    bun run check

justfile

···
 # stop dev services
 dev-services-down:
     docker compose down
+
+# expose backend via ngrok tunnel
+tunnel:
+    ngrok http 8001 --domain tunnel.zzstoatzz.io