docs: rework UI flow sketches — browser chrome, URLs, extension layout, browser-wallet provider-connect steps

[AquiGorka]

Summary

Reworks the 26 lofi UI flow sketches from #102 per PM design review. Each screen now sits inside a browser-window or extension-popup container so the wireframes read as actual rendered pages.

Changes by category

• Browser-window chrome (4 web SPAs — provider-console, council-console, network-dashboard, moonlight-pay): every screen wrapped in a chrome rectangle (light-gray border, semi-transparent) with traffic-light dots + an address bar showing the URL the screen renders. Containers larger than the inner page with visible inner padding; navbar pinned flush against the URL bar at the top.
• Extension-popup chrome (browser-wallet, 6 flows): every screen wrapped in a rounded popup-shaped container with a small extension-toolbar icon at top-right; navbar pinned flush at the top.
• URLs in address bars (4 web apps): derived directly from each app's router config —
  • provider-console: #/login, #/home, #/setup/metadata, #/setup/fund, #/setup/join, #/recover, #/provider/:pk
  • council-console: #/login, #/, #/council, #/create-council/{metadata,fund,create,assets,invite}, #/recover-council, #/join
  • network-dashboard: single root URL (no router) — every flow-state shares it, drilldowns annotated via state captions
  • moonlight-pay: #/login, #/, #/admin, #/onboarding/{account,treasury}, #/pay/:merchant?amount=…&description=…
  • Modal-overlay screens keep the underlying route's URL (modals don't change the URL).
• Browser-wallet provider-connect screens added: 4 flows × 4 new screens = 16 new screens. The 4 flows that previously jumped straight from home to form now show the connect sequence first:
  • send-private-transfer.excalidraw — home (no privacy provider) → channel-picker (open) → sign-request (provider auth) → home (provider connected) → send
  • receive-private-address.excalidraw — same sequence before receive
  • deposit-and-activate.excalidraw — same sequence inserted between ramp and the deposit form
  • withdraw-to-public.excalidraw — same sequence before withdraw
• Combined canvas regenerated: sketches/all-sketches-combined.excalidraw rebuilt via python3 sketches/scripts/regen-combined.py. The regen script picks up the wider chrome boxes mechanically; no script change required.
• README updated: status block reflects the rework.

URL host derivation

Host strings use the testnet variants *-testnet.moonlightprotocol.io (provider-testnet, council-testnet, dashboard-testnet, pay-testnet) per PM Phase 0 confirmation. The original first-cut's per-screen labels (e.g. /login, /setup/metadata) carried over unchanged as the URL paths.

Test plan

• Open each per-flow .excalidraw and confirm the chrome wraps the screen with the URL string in the address bar
• Verify the 4 browser-wallet privacy flows show the provider-connect sequence before the form
• Open all-sketches-combined.excalidraw and confirm all 5 app rows render