docs: restructure website, optimize HTML, gitignore private files

Website docs (website/docs/):
- Delete 6 stale -md.html duplicates
- Rename docs-clients/miners/developers → clients/miners/developers.html
- Unify header/nav across all 15 pages (new .site-header pattern)
- Fix 34 dead href=# links with real targets
- Upgrade Font Awesome v4→v6 in index.html
- Replace search stub with live client-side search (15-page index)
- Extract all inline CSS into shared docs.css (+630 lines)
- Extract inline theme JS into shared theme.js
- Strip inline style= attributes from 10+ pages
- Add .announce-banner, .source-links, .search-results CSS classes
- Add Markdown Source links to clients/miners/developers pages
- Update components.html title to Architecture & Components
- Move browser-wallet.html to website/wallet/, leave redirect
- Update all dates to February 2026

Website root:
- Delete 6 root-level duplicate HTML files (160KB saved)
- Rewire index.html and 404.html links

Root README.md:
- Fix 8 broken doc links to new numbered folder structure
- Update copyright to 2026

.gitignore + .example files:
- Gitignore private files: .aitbc.yaml, .env, deploy scripts,
  GPU scripts, service scripts, infra configs, .windsurf/, website README
- Create 7 .example files for GitHub users with sanitized templates
- Untrack 47 previously committed private files

Live server:
- Push all website files to aitbc-cascade:/var/www/html/
- Clean stale admin.html and index.nginx-debian.html

website/README.md

@@ -1,37 +0,0 @@
-# AITBC Website
-
-This folder contains the complete AITBC platform website, updated to reflect the current production-ready state.
-
-## Files Structure
-
-- `index.html` - Main homepage with platform components and achievements
-- `docs/` - Documentation folder (moved to container docs directory)
-  - `docs-index.html` - Documentation landing page
-  - `docs-miners.html` - Miner-specific documentation
-  - `docs-clients.html` - Client-specific documentation  
-  - `docs-developers.html` - Developer-specific documentation
-- `documentation.html` - Legacy full documentation page
-- `full-documentation.html` - Comprehensive technical documentation
-- `404.html` - Custom error page
-- `aitbc-proxy.conf` - Nginx reverse proxy configuration
-
-## Deployment
-
-The website is deployed in the AITBC Incus container at:
-- Container IP: 10.1.223.93
-- Domain: aitbc.bubuit.net
-- Documentation: aitbc.bubuit.net/docs/
-
-## Key Updates Made
-
-1. **Production-Ready Messaging**: Changed from concept to actual platform state
-2. **Platform Components**: Showcases 7 live components (Blockchain Node, Coordinator API, Marketplace, Explorer, Wallet, Pool Hub, GPU Services)
-3. **Achievements Section**: Real metrics (30+ GPU services, Stages 1-7 complete)
-4. **Updated Roadmap**: Reflects current development progress
-5. **Documentation Structure**: Split by audience (Miners, Clients, Developers)
-
-## Next Steps
-
-- Configure SSL certificate for HTTPS
-- Set up DNS for full domain accessibility
-- Consider adding live network statistics dashboard