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/creative/assembler.py

@@ -28,8 +28,26 @@ try:
 except ImportError:
     _MOVIEPY_AVAILABLE = False
 
-# Resolve a font that actually exists on this system.
-_DEFAULT_FONT = "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf"
+def _resolve_font() -> str:
+    """Find a usable TrueType font on the current platform."""
+    candidates = [
+        # Linux (Debian/Ubuntu)
+        "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+        "/usr/share/fonts/TTF/DejaVuSans.ttf",  # Arch
+        "/usr/share/fonts/dejavu-sans-fonts/DejaVuSans.ttf",  # Fedora
+        # macOS
+        "/System/Library/Fonts/Supplemental/Arial.ttf",
+        "/System/Library/Fonts/Helvetica.ttc",
+        "/Library/Fonts/Arial.ttf",
+    ]
+    for path in candidates:
+        if Path(path).exists():
+            return path
+    logger.warning("No system TrueType font found; using Pillow default")
+    return "Helvetica"
+
+
+_DEFAULT_FONT = _resolve_font()
 
 
 def _require_moviepy() -> None: