Publish Editor and MCP guides, generate the MCP tool reference, and describe account email

[callumalpass]

This publishes the uncommitted work left in the canonical checkout on 2026-09-26, rebuilt on current main. Main's Reader guides and docs-sections.ts (#74) are kept; the branch's older copies of them are dropped.

• Editor guide (/apps/editor/, 6 pages) and MCP guide (/apps/mcp/, 6 pages), added as docs sections alongside SDK, Reader and Writer. The apps catalogue links to them.
• MCP tool reference generated by scripts/sync-mcp-tools.mjs, which builds services/mcp from the pinned Connect ref and lists the tools the server actually registers. Following Stop tracking generated sources; sync them in the Connect release update #80, src/data/mcp-tools.json is untracked and generated by sync:sources. CI, deploy and the release update build the MCP server first, with Connect's own pnpm version; its Node 24 engine gives only a warning on Node 22. At beta125 the reference has 16 tools; the stale committed copy was from beta110.
• Privacy page Email section. Checked against Connect's email code (migration 0034, beta-welcome-email): the welcome message exists, announcements are on by default and can be turned off, product updates are opt-in, and every non-essential message carries an unsubscribe token.

Fact-check. Both guides were drafted against about beta110, and every concrete claim was checked against Connect 5548e106 (beta125) and the pinned mdbase-rs. Corrections:

• Editor:
  • Approval scope: reading is required; the other permissions are optional toggles.
  • The rail filters by folder, tag or type rather than grouping.
  • Rename behaviour; Use latest; the 7-day recovery of unsaved edits.
  • Audio, video, text and block embeds; multi-file attach.
  • Type creation labels and the real membership logic: explicit type keys win, otherwise all conditions must match.
  • Uniqueness scopes; YAML and Read defaults labels.
  • Owner-only People & sharing; seven-day expiry.
  • Missing shortcuts: Ctrl K outside the note text, ↑/↓.
• MCP:
  • describe_collection doesn't report approved operations or local/hosted; list_connections does.
  • The check_backlinks default is false.
  • Conflicts return valid: false with a concurrent_modification diagnostic.
  • Cursor limits and expiry; mutation_request_conflict.
  • Extra troubleshooting codes.
• MCP data handling:
  • Tokens are stored as hashes.
  • Private keys are encrypted, but message counters are not.
  • The hosted provider can read hosted collections.
  • It now states plainly that expired sign-in records are not deleted automatically, and how errors are logged.

The reviewer suggested that invalid changes are written by default, which is not the case: v0.3 collections default to error validation (mdbase-rs src/config/mod.rs:117-120), so that claim was kept. Production sign-up is open (/v1/auth/config) and hosted sharing is enabled.

pnpm test passes after syncing at the pinned refs, with 60 pages and no broken links.