Initial tablet POC: project restructure + WebSocket/HTTP server + JS client

- Restructured project into /app, /server, /client with run.py entry point
- WSServer (QWebSocketServer) with log_signal, start/stop, client tracking
- HTTP server serves /client on port 8080
- Vanilla JS client: faders, toggles, transport, drag-to-arrange, lock/save layout
- Start Tablet button + floating Tablet log window in app UI
- Preset broadcast on load/switch, DAW state relay, hardware sync via widget_update
- Widget colors synced from app palette, toggle state fixed (sends 0/127 correctly)
- Layout saved per preset UUID back to presets.json

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

app/palette.py

@@ -0,0 +1,45 @@
+PALETTE = [
+    ("Red",    "#e53935"),
+    ("Orange", "#fb8c00"),
+    ("Yellow", "#fdd835"),
+    ("Green",  "#43a047"),
+    ("Teal",   "#00897b"),
+    ("Blue",   "#1e88e5"),
+    ("Purple", "#8e24aa"),
+    ("Pink",   "#e91e63"),
+    ("White",  "#f5f5f5"),
+    ("Gray",   "#4a5568"),
+]
+
+PALETTE_NAMES = [p[0] for p in PALETTE]
+PALETTE_HEX = {p[0]: p[1] for p in PALETTE}
+
+PALETTE_VIVID = {
+    "Red":    "#7f0000",
+    "Orange": "#7f3000",
+    "Yellow": "#7f6000",
+    "Green":  "#1b5e20",
+    "Teal":   "#004d40",
+    "Blue":   "#0d2b6e",
+    "Purple": "#4a0072",
+    "Pink":   "#7f004d",
+    "White":  "#9e9e9e",
+    "Gray":   "#263238",
+}
+
+def lighten_hex(hex_color, amount=0):
+    hex_color = hex_color.lstrip("#")
+    r, g, b = int(hex_color[0:2], 16), int(hex_color[2:4], 16), int(hex_color[4:6], 16)
+    r = min(255, r + amount)
+    g = min(255, g + amount)
+    b = min(255, b + amount)
+    return f"#{r:02x}{g:02x}{b:02x}"
+
+
+def darken_hex(hex_color, amount=60):
+    hex_color = hex_color.lstrip("#")
+    r, g, b = int(hex_color[0:2], 16), int(hex_color[2:4], 16), int(hex_color[4:6], 16)
+    r = max(0, r - amount)
+    g = max(0, g - amount)
+    b = max(0, b - amount)
+    return f"#{r:02x}{g:02x}{b:02x}"