v0.8.0 — first versioned release

First versioned release. The project was already public at
cli2ui.com; this tags the current, mature PostgreSQL-only
state as the baseline (0.8 reflecting how much is already built, with 1.0
reserved for multi-DB support).

Added

• Read-only and write-mode SQL runner, with query result export to CSV/JSON
  (streamed, full result set).
• Object browser: databases, schemas, tables, columns, indexes, constraints.
• Table operations: create/rename/drop, column add/rename/type/null/default
  changes, with automatic snapshot before destructive changes.
• Database operations: create, clone, rename, drop, and ALTER schema/role.
• Backup & restore via pg_dump/psql with streaming restore, restore into a
  new or existing database, and an auto-backup total-size retention cap.
• Activity, Locks/blocking, Health (sizes, unused indexes, dead rows, bloat
  estimate), and Replication (readiness, WAL position, slots, standby setup
  recipe) panels.
• Command history.
• Optional planner_lab app (scale simulation + index lab), decoupled behind a
  feature flag.
• Internationalisation (English / Japanese).
• Workspace overview dashboard and unified UI (design system).