v0.4.0

Upgrade notes

• Database migration (schema 9 → 10). The first start of v0.4.0 adds the
  Portal relay listing column. Before migrating, Flats copies flats.db to
  <data>/backups/. Downgrading to v0.3.0 needs that backup restored; an
  older binary refuses a newer schema. Back up the data directory before
  upgrading. See Releases and installation.
• Upgrade: run the installer again. It replaces the binary and restarts a
  running service with its existing settings.
• New optional setting portal.hide (default false). Public flats stay
  listed on Portal relays unless you turn it on or override a flat. Hiding is
  not access control: anyone with the URL can still open the flat. No
  config.json change is needed.
• No CLI flag changes.

What's Changed

• feat(mcp): serve agent guidance on demand through a guide tool by @oesni in #35
• feat(docs): drop brand and file paths, assign random names, add footer by @oesni in #36
• feat(mcp): add page design guide and non-blocking save warnings by @oesni in #38
• feat(portal): let the operator hide public flats from relay listings by @oesni in #41
• feat(docs): replace Edit/Split/Preview with a single live-preview view by @oesni in #43
• fix: open the Tailscale route when it is granted to a live flat by @oesni in #40
• fix(portal): describe portal_hidden as the requested relay listing by @oesni in #42
• feat(docs): add a private Edit/View toggle to the live-preview surface by @oesni in #39
• feat(mcp): add typed server runtime contract as guide topic.server.types by @oesni in #44
• feat(mcp): add update_document for guarded live docs edits by @oesni in #46
• feat(mcp): guide agents to check previews in their own browser by @oesni in #49
• docs: tighten README and split operator and agent guides by @oesni in #45

Full Changelog: v0.3.0...v0.4.0