Port all web CSS token themes to TUI via shared vocabulary (accent, dim,
muted, ok, todo, event, remind, danger). Styles rebuild from active
theme on switch. Press T to cycle, persists to ~/.nib/theme. Glamour
markdown renderer respects light/dark per theme.
Persistent left panel showing tags with counts. Provides ambient
awareness of tag landscape without requiring a modal.
- New tagRailModel in tagrail.go: tag list with cursor, scroll, counts
- Rail visible at >=100 cols width, 18% width (min 16 chars)
- ctrl+b toggles rail visibility
- focusTagRail added to focus cycle: capture → tags → list → detail
- j/k navigates, enter filters/unfilters by tag
- Active filter tag highlighted bold in rail
- Tags refresh after entity create/delete/absorb
- Rail auto-hides on narrow terminals, # modal still works as fallback
- Width allocation accounts for rail in split and non-split layouts