feat: Add charmbracelet TUI for gt feed (gt-u7dxq)

- Add bubbletea and bubbles dependencies
- Create internal/tui/feed package with:
  - model.go: Main bubbletea model with agent tree and event stream
  - view.go: Rendering logic with lipgloss styling
  - keys.go: Vim-style key bindings (j/k, tab, /, q)
  - styles.go: Color palette and component styles
  - events.go: Event source from bd activity
- Update gt feed to use TUI by default (--plain for text mode)
- TUI features: agent tree by role, event stream, keyboard nav

Closes gt-be0as, gt-lexye, gt-1uhmj

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/tui/feed/styles.go

@@ -0,0 +1,118 @@
+// Package feed provides a TUI for the Gas Town activity feed.
+package feed
+
+import "github.com/charmbracelet/lipgloss"
+
+// Color palette
+var (
+	colorPrimary   = lipgloss.Color("12")  // Blue
+	colorSuccess   = lipgloss.Color("10")  // Green
+	colorWarning   = lipgloss.Color("11")  // Yellow
+	colorError     = lipgloss.Color("9")   // Red
+	colorDim       = lipgloss.Color("8")   // Gray
+	colorHighlight = lipgloss.Color("14")  // Cyan
+	colorAccent    = lipgloss.Color("13")  // Magenta
+)
+
+// Styles for the feed TUI
+var (
+	// Header styles
+	HeaderStyle = lipgloss.NewStyle().
+			Bold(true).
+			Foreground(colorPrimary).
+			Padding(0, 1)
+
+	TitleStyle = lipgloss.NewStyle().
+			Bold(true).
+			Foreground(lipgloss.Color("15"))
+
+	FilterStyle = lipgloss.NewStyle().
+			Foreground(colorDim)
+
+	// Agent tree styles
+	TreePanelStyle = lipgloss.NewStyle().
+			Border(lipgloss.RoundedBorder()).
+			BorderForeground(colorDim).
+			Padding(0, 1)
+
+	RigStyle = lipgloss.NewStyle().
+			Bold(true).
+			Foreground(colorPrimary)
+
+	RoleStyle = lipgloss.NewStyle().
+			Foreground(colorAccent)
+
+	AgentNameStyle = lipgloss.NewStyle().
+			Foreground(lipgloss.Color("15"))
+
+	AgentActiveStyle = lipgloss.NewStyle().
+				Foreground(colorSuccess)
+
+	AgentIdleStyle = lipgloss.NewStyle().
+			Foreground(colorDim)
+
+	// Event stream styles
+	StreamPanelStyle = lipgloss.NewStyle().
+				Border(lipgloss.RoundedBorder()).
+				BorderForeground(colorDim).
+				Padding(0, 1)
+
+	TimestampStyle = lipgloss.NewStyle().
+			Foreground(colorDim)
+
+	EventCreateStyle = lipgloss.NewStyle().
+				Foreground(colorSuccess)
+
+	EventUpdateStyle = lipgloss.NewStyle().
+				Foreground(colorPrimary)
+
+	EventCompleteStyle = lipgloss.NewStyle().
+				Foreground(colorSuccess).
+				Bold(true)
+
+	EventFailStyle = lipgloss.NewStyle().
+			Foreground(colorError).
+			Bold(true)
+
+	EventDeleteStyle = lipgloss.NewStyle().
+				Foreground(colorWarning)
+
+	// Status bar styles
+	StatusBarStyle = lipgloss.NewStyle().
+			Background(lipgloss.Color("236")).
+			Foreground(colorDim).
+			Padding(0, 1)
+
+	HelpKeyStyle = lipgloss.NewStyle().
+			Foreground(colorHighlight).
+			Bold(true)
+
+	HelpDescStyle = lipgloss.NewStyle().
+			Foreground(colorDim)
+
+	// Focus indicator
+	FocusedBorderStyle = lipgloss.NewStyle().
+				Border(lipgloss.RoundedBorder()).
+				BorderForeground(colorPrimary).
+				Padding(0, 1)
+
+	// Role icons
+	RoleIcons = map[string]string{
+		"mayor":    "🎩",
+		"witness":  "👁",
+		"refinery": "🏭",
+		"crew":     "👷",
+		"polecat":  "😺",
+		"deacon":   "🔔",
+	}
+
+	// Event symbols
+	EventSymbols = map[string]string{
+		"create":   "+",
+		"update":   "→",
+		"complete": "✓",
+		"fail":     "✗",
+		"delete":   "⊘",
+		"pin":      "📌",
+	}
+)