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/run.go

@@ -0,0 +1,116 @@
+package tui
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+type runStep struct {
+	Text string `json:"text"`
+	Done bool   `json:"done"`
+}
+
+type runModel struct {
+	steps    []runStep
+	cursor   int
+	entityID string
+	dirty    bool
+}
+
+func newRunModel(entityID string, cardData *string) runModel {
+	m := runModel{entityID: entityID}
+	m.steps = parseChecklist(cardData)
+	return m
+}
+
+func parseChecklist(cardData *string) []runStep {
+	if cardData == nil {
+		return nil
+	}
+	var data struct {
+		Steps []runStep `json:"steps"`
+	}
+	if err := json.Unmarshal([]byte(*cardData), &data); err != nil {
+		return nil
+	}
+	return data.Steps
+}
+
+func (r runModel) stepsJSON() string {
+	b, _ := json.Marshal(map[string]any{"steps": r.steps})
+	return string(b)
+}
+
+func (r runModel) doneCount() int {
+	n := 0
+	for _, s := range r.steps {
+		if s.Done {
+			n++
+		}
+	}
+	return n
+}
+
+func (r runModel) update(key string) runModel {
+	switch key {
+	case "up", "k":
+		if r.cursor > 0 {
+			r.cursor--
+		}
+	case "down", "j":
+		if r.cursor < len(r.steps)-1 {
+			r.cursor++
+		}
+	case " ":
+		if r.cursor < len(r.steps) {
+			r.steps[r.cursor].Done = !r.steps[r.cursor].Done
+			r.dirty = true
+		}
+	case "r":
+		for i := range r.steps {
+			r.steps[i].Done = false
+		}
+		r.dirty = true
+	}
+	return r
+}
+
+func (r runModel) view(width int) string {
+	if len(r.steps) == 0 {
+		return statusStyle.Render("no steps")
+	}
+
+	var b strings.Builder
+	done := r.doneCount()
+	total := len(r.steps)
+	pct := 0
+	if total > 0 {
+		pct = done * 100 / total
+	}
+
+	header := fmt.Sprintf("▶ running   %d/%d done (%d%%)", done, total, pct)
+	b.WriteString(detailHeaderStyle.Render(header))
+	b.WriteString("\n\n")
+
+	for i, step := range r.steps {
+		var line string
+		if step.Done {
+			line = checkDoneStyle.Render("[✓] " + step.Text)
+		} else {
+			line = checkPendingStyle.Render("[ ] " + step.Text)
+		}
+
+		if i == r.cursor {
+			b.WriteString(selectedItemStyle.Render(" " + line))
+		} else {
+			b.WriteString(listItemStyle.Render(line))
+		}
+		b.WriteString("\n")
+	}
+
+	b.WriteString("\n")
+	b.WriteString(helpStyle.Render("space:toggle  r:reset  esc:save+exit"))
+
+	return b.String()
+}