feat(tui): add search via capture bar and absorb flow

Search uses existing parse grammar ?prefix — type `?query #tag` in
capture bar to filter entities client-side. Substring match on
body+title+description with AND tag filtering. Esc clears search.

Absorb via m key on fluid entities — opens source picker showing all
other entities, enter merges source into target. Uses existing
store.Absorb() backend.

internal/tui/list.go

@@ -13,6 +13,7 @@ import (
 
 type listModel struct {
 	entities []*db.Entity
+	filtered []*db.Entity
 	cursor   int
 	offset   int
 	height   int
@@ -25,6 +26,7 @@ func newListModel() listModel {
 
 func (l *listModel) setEntities(entities []*db.Entity) {
 	l.entities = entities
+	l.filtered = nil
 	if l.cursor >= len(entities) {
 		l.cursor = max(0, len(entities)-1)
 	}
@@ -35,11 +37,19 @@ func (l *listModel) setSize(width, height int) {
 	l.height = height
 }
 
+func (l listModel) displayEntities() []*db.Entity {
+	if l.filtered != nil {
+		return l.filtered
+	}
+	return l.entities
+}
+
 func (l listModel) selected() *db.Entity {
-	if len(l.entities) == 0 || l.cursor >= len(l.entities) {
+	ents := l.displayEntities()
+	if len(ents) == 0 || l.cursor >= len(ents) {
 		return nil
 	}
-	return l.entities[l.cursor]
+	return ents[l.cursor]
 }
 
 func (l listModel) update(msg tea.KeyMsg) listModel {
@@ -52,7 +62,7 @@ func (l listModel) update(msg tea.KeyMsg) listModel {
 			}
 		}
 	case "down", "j":
-		if l.cursor < len(l.entities)-1 {
+		if l.cursor < len(l.displayEntities())-1 {
 			l.cursor++
 			visible := l.visibleCount()
 			if l.cursor >= l.offset+visible {
@@ -63,7 +73,7 @@ func (l listModel) update(msg tea.KeyMsg) listModel {
 		l.cursor = 0
 		l.offset = 0
 	case "end", "G":
-		l.cursor = max(0, len(l.entities)-1)
+		l.cursor = max(0, len(l.displayEntities())-1)
 		visible := l.visibleCount()
 		if l.cursor >= visible {
 			l.offset = l.cursor - visible + 1
@@ -74,7 +84,7 @@ func (l listModel) update(msg tea.KeyMsg) listModel {
 			l.offset = l.cursor
 		}
 	case "pgdown", "ctrl+d":
-		l.cursor = min(len(l.entities)-1, l.cursor+l.visibleCount())
+		l.cursor = min(len(l.displayEntities())-1, l.cursor+l.visibleCount())
 		visible := l.visibleCount()
 		if l.cursor >= l.offset+visible {
 			l.offset = l.cursor - visible + 1
@@ -84,11 +94,12 @@ func (l listModel) update(msg tea.KeyMsg) listModel {
 }
 
 func (l listModel) view(width int) string {
-	if len(l.entities) == 0 {
+	ents := l.displayEntities()
+	if len(ents) == 0 {
 		return statusStyle.Render("no entities")
 	}
 
-	groups := groupByDate(l.entities)
+	groups := groupByDate(ents)
 
 	type displayLine struct {
 		text      string