feat: mobile-optimized layout + phone access instructions

CSS:
- Responsive grid: 2-col desktop → 1-col mobile (≤768px)
- Sidebar becomes horizontal scroll strip on mobile
- 100dvh for correct mobile viewport height
- env(safe-area-inset-*) for iPhone notch/home bar
- 16px input font-size prevents iOS auto-zoom
- 44px min touch targets on input + send button
- touch-action: manipulation stops double-tap zoom
- overscroll-behavior: none prevents iOS bounce bleed
- -webkit-overflow-scrolling: touch for smooth scroll

HTML (base.html):
- viewport-fit=cover for full-bleed on notched iPhones
- apple-mobile-web-app-capable + status-bar-style meta
- theme-color meta (#060d14)

README:
- "Access from your phone" section with exact steps:
  --host 0.0.0.0, ipconfig getifaddr en0, same-WiFi note

https://claude.ai/code/session_01M4L3R98N5fgXFZRvV8X9b6

README.md

@@ -65,6 +65,38 @@ Open your browser to **http://localhost:8000**
 
 ---
 
+## Access from your phone
+
+The dashboard is mobile-optimized. To open it on your phone:
+
+**Step 1 — bind to your local network** (instead of just localhost):
+
+```bash
+uvicorn dashboard.app:app --host 0.0.0.0 --port 8000 --reload
+```
+
+**Step 2 — find your Mac's IP address:**
+
+```bash
+ipconfig getifaddr en0
+```
+
+This prints something like `192.168.1.42`. If you're on ethernet instead of Wi-Fi, try `en1`.
+
+**Step 3 — open on your phone:**
+
+Make sure your phone is on the **same Wi-Fi network** as your Mac, then open:
+
+```
+http://192.168.1.42:8000
+```
+
+(replace with your actual IP)
+
+On mobile the layout switches to a single column — status panels become a horizontal scroll strip at the top, chat fills the rest of the screen. The input field is sized to prevent iOS from zooming in when you tap it.
+
+---
+
 ## What you'll see
 
 The dashboard has two panels on the left and a chat window on the right: