37584670eb
Builds out two half-finished view features: Group collapse: - AxisEntry enum distinguishes GroupHeader from DataItem on grid axes - expand_category() emits group headers and filters collapsed items - Grid renders inline group header rows with ▼/▶ indicator - `z` keybinding toggles collapse of nearest group above cursor Hide/show item: - Restore show_item() (was commented out alongside hide_item) - Add HideItem / ShowItem commands and dispatch - `H` keybinding hides the current row item - `:show-item <cat> <item>` command to restore hidden items - Restore silenced test assertions for hide/show round-trip Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>