feat: add TOTP 2FA, API key switcher, login progress bar, and alpha hardening plan

- TOTP 2FA: full setup/confirm/disable/login flow with Argon2id + ChaCha20-Poly1305
  encrypted secret storage, QR code generation, and bcrypt-hashed backup codes
- API key switcher: OAuth vs personal API key toggle in AIUI chat settings with
  status indicator, key validation, and help text
- Login progress bar: server startup detection with health check polling, form
  disabled until server is ready
- AI quarantine docs: comprehensive HTML page documenting all 6 security layers
- Settings: AI Data Access permission toggles with per-category control
- Alpha hardening plan: 28-task overnight automation plan across 7 phases
  (onboarding, login, app install, AIUI, UI polish, security, ISO build)
- Backlog: node discovery spatial map feature for alpha demo

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

core/archipelago/Cargo.toml

@@ -62,10 +62,16 @@ reqwest = { version = "0.11", features = ["json", "socks"] }
 # Nostr (node discovery)
 nostr-sdk = "0.44"
 
-# Backup encryption (DID identity export)
+# Backup encryption (DID identity export) + TOTP 2FA encryption
 argon2 = "0.5"
 chacha20poly1305 = "0.10"
 base64 = "0.21"
 
+# TOTP 2FA
+totp-rs = { version = "5.7", features = ["otpauth", "gen_secret"] }
+qrcode = "0.14"
+data-encoding = "2.6"
+zeroize = { version = "1.7", features = ["derive"] }
+
 [dev-dependencies]
 tokio-test = "0.4"