v0.5.0

New features:

• "Specs" grouping — spec files auto-tagged "specs", shown under collapsible "Specs" section in both TUI dashboard/task board and
  web dashboard/tasks
• "Other" archive sub-group — archived items without plan or specs tags get their own section
• r refresh keybinding in TUI
• Config persistence — serve and statuses settings saved by save_config()

Infrastructure:

• Sandboxed devcontainer with scoped GitHub token, Claude Code auth, shell history persistence
• System specs added (parsing, scanning, models, config, tui, web, history)
• Updated archive convention (move done tasks, not whole sections)

Tests: 187 → 230