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/statusbar.go

@@ -38,7 +38,14 @@ func countText(m model) string {
 func contextHints(m model) string {
 	switch m.state {
 	case stateDetail:
-		return "p:promote D:demote c:copy e:edit !:pin esc:back"
+		switch m.detail.mode {
+		case detailRun:
+			return "space:toggle  j/k:nav  r:reset  esc:save+exit"
+		case detailFill:
+			return "tab:next  shift+tab:prev  enter:copy  esc:cancel"
+		default:
+			return "p:promote D:demote c:copy e:edit r:run f:fill !:pin esc:back"
+		}
 	case stateInput:
 		return "enter:submit esc:cancel"
 	case stateTagFilter: