feat(wiki): page revision history with diff, revert, and manual editing

[lyingbug]

Summary

• Add immutable wiki page revision snapshots on every content-changing edit, with edit provenance (user / agent / pipeline / revert) and two-tier retention (pipeline snapshots pruned sooner; human/agent/revert kept longer).
• Expose revision list/get/revert APIs with optimistic-locking on PUT /wiki/pages/*slug, and wire agent tools to attribute writes correctly.
• Ship a Wiki browser UI for inline editing, version history drawer with line diff, revert, and create/delete page flows; consolidate the schema into SQLite 000000_init plus Postgres migration 000075.

Test plan

• Edit a wiki page in the browser; confirm version increments and history drawer shows the prior snapshot
• Open two tabs, edit the same page, and verify the second save surfaces a 409 conflict with reload/overwrite options
• Revert to an older revision and confirm content restores while version advances and a new snapshot is created
• Run agent wiki tools on a page and confirm last_edit_source shows agent in history
• Apply migration 000075 on Postgres and verify fresh SQLite Lite installs include wiki_page_revisions
• go test ./internal/application/service/ ./internal/application/repository/ ./internal/router/ -run Wiki
• npx tsx --test frontend/src/utils/wikiLineDiff.test.ts