Rebind char cycling to ,/. instead of [/]

[ and ] needed a reach/shift on most layouts and felt awkward next to
the otherwise all-unshifted control scheme (hjkl, space, digits). ,
and . are adjacent, unshifted, easy to hit without looking away from
the canvas -- a natural prev/next pair. Old bindings kept as a fallback
rather than removed.

Verified both in isolation (Update() with a KeyMsg) and live over a
real SSH session -- the status-line ink swatch visibly cycles from █
to ▓ on a fresh connection. An initial live test after the rebind
appeared to fail, but that traced to a stale session left over from
the server restart, not an actual bug -- confirmed working correctly
on a fresh connection.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

game/model.go

@@ -80,9 +80,9 @@ func (m Model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 			m.canvas.Paint(cur.X, cur.Y, ' ', "")
 		}
 
-	case "[":
+	case ",", "[":
 		m.charIdx = (m.charIdx - 1 + len(charPalette)) % len(charPalette)
-	case "]":
+	case ".", "]":
 		m.charIdx = (m.charIdx + 1) % len(charPalette)
 
 	case "1", "2", "3", "4", "5", "6", "7", "8":

game/model_test.go

@@ -118,3 +118,27 @@ func newTestRenderer() *lipgloss.Renderer {
 	r.SetColorProfile(termenv.TrueColor)
 	return r
 }
+
+func TestCommaPeriodCharCycling(t *testing.T) {
+	c := NewCanvas()
+	m := NewModel(c, "test-id", "tester", newTestRenderer())
+	c.Join("test-id", "tester", nil)
+
+	mi, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune("x")}) // exit intro
+	m = mi.(Model)
+
+	t.Logf("charIdx before: %d", m.charIdx)
+	mi, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune(".")})
+	m = mi.(Model)
+	t.Logf("charIdx after '.': %d", m.charIdx)
+	if m.charIdx != 1 {
+		t.Fatalf("expected charIdx=1 after '.', got %d", m.charIdx)
+	}
+
+	mi, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune(",")})
+	m = mi.(Model)
+	t.Logf("charIdx after ',': %d", m.charIdx)
+	if m.charIdx != 0 {
+		t.Fatalf("expected charIdx=0 after ',', got %d", m.charIdx)
+	}
+}

game/view.go

@@ -42,7 +42,7 @@ func (m Model) renderIntro() string {
 		dim.Render("a shared doodle wall, one keystroke at a time") + "\n\n" +
 		"Everyone connected right now is drawing on the same canvas.\n" +
 		"Move with arrow keys or hjkl, space/enter to paint, backspace to\n" +
-		"erase. [ and ] cycle the ink character, 1-8 pick a color, c clears\n" +
+		"erase. , and . cycle the ink character, 1-8 pick a color, c clears\n" +
 		"everything for everyone (yes, really — it's a shared wall).\n\n" +
 		dim.Render("press any key to start")
 	return m.boxStyle().Render(body)
@@ -112,7 +112,7 @@ func (m Model) renderCanvas() string {
 
 	inkSwatch := m.style().Foreground(lipgloss.Color(inkPalette[m.inkColorIdx])).Render(string(charPalette[m.charIdx]))
 	dim := m.style().Foreground(lipgloss.Color("#777777"))
-	status := fmt.Sprintf("ink %s  (1-8 color, [ ] char)   peers: %d   %s",
+	status := fmt.Sprintf("ink %s  (1-8 color, , . char)   peers: %d   %s",
 		inkSwatch, m.canvas.PeerCount(), dim.Render("space paint · c clear · q quit"))
 
 	return m.boxStyle().Render(b.String() + "\n" + status)