feat: rebuild the SagaSmithAI organization site

[dajiaohuang]

Summary

• rebuild the bilingual organization site around the current SagaSmith Web visual language and the Local/Hosted product boundary
• replace the old release-input model with a self-contained static Pages build and PR validation
• add current installation, architecture, repository topology, Content Pack, updates, security, privacy, manifest, SEO/Open Graph, and 404 surfaces
• centralize current repository/status data and mark archived repositories as history rather than compatibility or release inputs

Product and content boundaries

• documents sagasmith.authoritative-mcp/v1 as the shared Local/Hosted contract
• keeps SagaSmith Web responsibilities distinct from authoritative domain MCP state
• reflects the current Agent, Web, core, D&D, CoC, Narrative, content-library, and organization repositories
• preserves honest Early Alpha / testing / Alpha / Experimental maturity labels

Assets

• retains the website's existing first-party brand marks
• adds reviewable site-owned SVG sources for the 1200x630 Open Graph card and exact 512x512 manifest icon
• copies no SagaSmith Web proprietary source, texture, icon, backend implementation, model, cache, or generation workflow
• loads no remote fonts, analytics, image CDN, or third-party visual assets

Validation

• npm ci
• npm run check
• npm run check:external — 17 unique external URLs, 0 warnings
• git diff --check
• staged credential-pattern scan
• Playwright/Chromium: 8 desktop routes and 4 representative mobile routes; keyboard skip link, mobile-menu keyboard/Escape behavior, language persistence, reduced motion, contrast, console errors, failed requests, and horizontal overflow

Pages behavior

Pull requests build and validate the site without deploying. Pushes to main and explicit workflow dispatches publish only this repository's dist/ artifact.