v0.5.0

v0.5.0 — realtime sync through a hub API

The hub grows from "just Postgres" into an API server in front of Postgres — the
foundation for multi-user collaboration (design: docs/hub-api.md). Sync can now ride an
authenticated HTTPS changeset protocol with realtime push, while the existing
direct-Postgres path keeps working unchanged: both transports coexist, per device,
behind a flag.

Realtime sync (opt-in)

• Hub API server (hub/api, Deno + Hono beside the Postgres container): a versioned
  POST /sync — mutations up, changes down — with per-device opaque bearer tokens and
  TLS terminated by Deno using the existing private-CA certs. Mint a device token on the
  hub, set syncViaApi/hubApi/hubApiToken in settings.json, and the 15s sync rides
  the API instead of raw SQL. Default off — nothing changes until you opt in.
• WS nudges: the API listens to Postgres once and pushes "something changed" over a
  WebSocket; the app then syncs immediately. Edits from another device appear in ~2s
  instead of on the next poll. The socket carries no data — a dropped connection costs
  latency, never correctness — and the poll stays as the fallback.
• Writes push fast too: a local edit schedules a sync ~1.5s later (debounced), so
  device-to-device latency is seconds in both directions.
• Change log: every write on hub and laptops is captured by triggers into a
  change_log (monotonic revision = the API's pull cursor). Legacy direct-SQL writes are
  captured the same way, so mixed fleets stay consistent during the transition.

Identity

• Users and devices are first-class: a synced users profile (name/avatar) and a
  devices table mapping each machine to its user. Comments now carry a durable
  author_id and pages an owner_id, backfilled for existing data. Setting "Your name"
  in ⚙ Settings updates the synced profile — other machines render it even before
  configuring their own.

Configuration

• TRACKER_CLIENTS env var replaces the hardcoded client-name mapping used by the
  session importers and /trame:track (empty → everything files under Side-projects).

Deploy

• hub/deploy.sh now re-applies the idempotent schema.sql on every deploy (schema
  changes finally reach an existing hub) and restarts the API container so it picks up
  the copied source. The compose stack gains the tracker-api service on :8443,
  DB access scoped to the docker subnet in pg_hba.