feat: Add AgentBar arc dock with per-agent terminal frame and voice modal

- Add ui.json configs for Main (purple) and Ejecutor (red) agents
- AgentBar: fused arc-shaped dock at bottom with dynamic glow
- Quick press opens styled terminal frame mockup
- Hold opens voice modal with Web Speech API streaming transcription
- Responsive: full-width mobile, max-width on tablet/desktop/4K
- Agents API: serve uiConfig from ui.json in agent directories
- Agents page: route, store, toolbar integration

.claude/ui.json

@@ -0,0 +1,9 @@
+{
+  "label": "Main",
+  "shortLabel": "M",
+  "color": "#6366f1",
+  "gradient": "linear-gradient(135deg, #6366f1, #8b5cf6)",
+  "terminalBg": "#0f0a1a",
+  "terminalBorder": "#6366f1",
+  "enabled": true
+}