Clarify the website journey and clear the nanoid advisory

[aryamthecodebreaker]

What changed

• Reworked the homepage around a plain-language problem, outcome, and proof journey.
• Simplified the live demo with progressive disclosure and clearer result labels.
• Changed setup to a run-once-first flow with separate agent, terminal, PR, and advanced MCP paths.
• Fixed the mobile demo width constraint found during browser review.
• Updated the nanoid override from 3.3.17 to 3.3.18 to clear GHSA-2v37-7h3g-55p8 while preserving the platform-optional lockfile entries.

Why

The existing site assumed too much developer context before explaining FixMap's value. The build also surfaced a high-severity audit advisory caused by the pinned nanoid version.

Impact

Visitors can understand what FixMap does before seeing installation details, try it once before installing, and use the demo without the previous information overload. Both npm audit gates now report zero vulnerabilities.

Validation

• Clean npm ci --prefer-offline --no-audit
• npm run audit:all
• npm run audit:production
• npm run typecheck -w @fixmap/web
• npm run lint -w @fixmap/web
• npm run build -w @fixmap/web
• Desktop and 390px mobile browser review
• Production route smoke for /, /get-started, and /demo