feat(tui): add interactive run mode for checklists and fill mode for templates

Run mode (r key on checklist cards): cursor navigates steps, space
toggles done/undone, r resets all, esc saves changes to DB and exits.
Persists step state — improvement over web which discards on exit.

Fill mode (f key on template cards): tab/shift-tab navigates slots,
type to fill values, enter resolves template and copies to clipboard
with use count increment. Esc cancels without copying.

Both modes are sub-states of detail view, keeping architecture simple.

internal/tui/keys.go

@@ -27,6 +27,8 @@ type keyMap struct {
 	Sort    key.Binding
 	Intent  key.Binding
 	Absorb  key.Binding
+	Run     key.Binding
+	Fill    key.Binding
 }
 
 var keys = keyMap{
@@ -54,4 +56,6 @@ var keys = keyMap{
 	Sort:    key.NewBinding(key.WithKeys("s"), key.WithHelp("s", "sort")),
 	Intent:  key.NewBinding(key.WithKeys("tab"), key.WithHelp("tab", "intent")),
 	Absorb:  key.NewBinding(key.WithKeys("m"), key.WithHelp("m", "absorb")),
+	Run:     key.NewBinding(key.WithKeys("r"), key.WithHelp("r", "run checklist")),
+	Fill:    key.NewBinding(key.WithKeys("f"), key.WithHelp("f", "fill template")),
 }