feat: add self-sufficient web console

[stackbilt-admin]

Summary

• add Vite-built embedded SPA served through the Worker ASSETS binding
• wire AegisVoiceAdapter through Agents SDK /agents routing with AEGIS_TOKEN enforcement
• configure wrangler example for ASSETS, CHAT_SESSION, AegisVoiceAdapter, DB, and AI
• make the browser console use Workers AI as the base chat path and bump release metadata to 0.8.0

Closes #40

Validation

• npm run build:ui
• npm run typecheck
• npm test
• npm pack --dry-run
• HOME=/tmp XDG_CONFIG_HOME=/tmp npx wrangler deploy --config wrangler.dryrun.toml --dry-run
• npx charter validate
• git -c core.whitespace=blank-at-eol,blank-at-eof,space-before-tab,cr-at-eol diff --cached --check