Simplify GPS to gpsd-only and streamline UI controls

Remove direct serial GPS dongle support in favor of gpsd daemon connectivity.
The UI now auto-connects to gpsd on page load and shows a GPS indicator when connected.
Simplify ADS-B dashboard controls bar for a cleaner, more compact layout.
Add setup-dev.sh for streamlined development environment setup.

- Remove GPSReader class and NMEA parsing (utils/gps.py)
- Consolidate to GPSDClient only with auto-connect endpoint
- Add GPS indicator with pulsing dot animation
- Compact controls bar with smaller fonts and tighter spacing
- Add aircraft database download banner/functionality

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

static/css/adsb_dashboard.css

@@ -478,11 +478,28 @@ body {
     grid-row: 2;
     display: flex;
     align-items: center;
-    flex-wrap: wrap;
-    gap: 10px 20px;
-    padding: 10px 20px;
+    flex-wrap: nowrap;
+    gap: 8px;
+    padding: 8px 15px;
     background: var(--bg-panel);
     border-top: 1px solid rgba(74, 158, 255, 0.3);
+    font-size: 11px;
+    overflow-x: auto;
+}
+
+.controls-bar label {
+    display: flex;
+    align-items: center;
+    gap: 3px;
+    white-space: nowrap;
+    cursor: pointer;
+}
+
+.controls-bar select,
+.controls-bar input[type="text"],
+.controls-bar input[type="number"] {
+    padding: 3px 5px;
+    font-size: 10px;
 }
 
 .control-group {
@@ -653,9 +670,11 @@ body {
 /* Airband Audio Controls */
 .airband-divider {
     width: 1px;
-    height: 24px;
-    background: var(--border-color);
-    margin: 0 10px;
+    height: 20px;
+    background: var(--accent-cyan);
+    opacity: 0.4;
+    margin: 0 5px;
+    flex-shrink: 0;
 }
 
 .airband-controls {
@@ -775,3 +794,32 @@ body {
     border-radius: 3px;
     background: rgba(0, 0, 0, 0.4);
 }
+
+/* GPS Indicator */
+.gps-indicator {
+    display: inline-flex;
+    align-items: center;
+    gap: 4px;
+    padding: 2px 8px;
+    background: rgba(34, 197, 94, 0.15);
+    border: 1px solid #22c55e;
+    border-radius: 12px;
+    font-size: 10px;
+    font-weight: 600;
+    color: #22c55e;
+    text-transform: uppercase;
+    letter-spacing: 0.5px;
+}
+
+.gps-indicator .gps-dot {
+    width: 6px;
+    height: 6px;
+    background: #22c55e;
+    border-radius: 50%;
+    animation: gps-pulse 2s ease-in-out infinite;
+}
+
+@keyframes gps-pulse {
+    0%, 100% { opacity: 1; transform: scale(1); }
+    50% { opacity: 0.5; transform: scale(0.8); }
+}