feat(analytics): add Pages-only usage statistics

[helbertm]

Summary

• inject the reviewed Umami loader only into the generated GitHub Pages artifact
• keep standalone, file://, local development, and release HTML tracker-free
• tag pageviews with hsqlite-editor-v<version> for version-level statistics
• honor DNT/GPC before any request and exclude URL query/hash data
• document the hosted privacy boundary in en-US, pt-BR, and es-ES

Privacy boundary

The integration does not send databases, SQL text, file names, queries, history, favorites, settings, recent-file metadata, exports, or tab content. The script URL and minimization controls are fixed in reviewed source; only the public Umami website UUID is supplied through GitHub Actions.

Validation

• npm run validate:full
• npm run validate:browser:quality (3 locales x desktop/mobile, zero axe violations)
• npm run validate:native:chromium (zero remote requests)
• npm run quality:docker (offline codex-quality gate, no leaks)
• generated Pages artifact: zero external requests on localhost and file://
• four specialist checkpoints: architecture, UX/accessibility, privacy/security, and execution

Deployment prerequisite

Configure the repository Actions variable UMAMI_WEBSITE_ID with the Umami website UUID before merge. The workflow fails closed when it is absent or malformed.