feat: single-command Docker startup, fix UI bugs, add Selenium tests

- Add `make up` / `make up DEV=1` for one-command Docker startup with
  optional hot-reload via docker-compose.dev.yml overlay
- Add `timmy up --dev` / `timmy down` CLI commands
- Fix cross-platform font resolution in creative assembler (7 test failures)
- Fix Ollama host URL not passed to Agno model (container connectivity)
- Fix task panel route shadowing by reordering literal routes before
  parameterized routes in swarm.py
- Fix chat input not clearing after send (hx-on::after-request)
- Fix chat scroll overflow (CSS min-height: 0 on flex children)
- Add Selenium UI smoke tests (17 tests, gated behind SELENIUM_UI=1)
- Install fonts-dejavu-core in Dockerfile for container font support
- Remove obsolete docker-compose version key
- Bump CSS cache-bust to v4

833 unit tests pass, 15 Selenium tests pass (2 skipped).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/dashboard/templates/base.html

@@ -11,7 +11,7 @@
   <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
   <link href="https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@300;400;500;700&display=swap" rel="stylesheet" />
   <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-QWTKZyjpPEjISv5WaRU9OFeRpok6YctnYmDr5pNlyT2bRjXh0JMhjY6hW+ALEwIH" crossorigin="anonymous" />
-  <link rel="stylesheet" href="/static/style.css?v=3" />
+  <link rel="stylesheet" href="/static/style.css?v=4" />
   {% block extra_styles %}{% endblock %}
   <script src="https://unpkg.com/htmx.org@2.0.3" integrity="sha384-0895/pl2MU10Hqc6jd4RvrthNlDiE9U1tWmX7WRESftEDRosgxNsQG/Ze9YMRzHq" crossorigin="anonymous"></script>
 </head>