Phase 5: TUI client (Bubbletea)

- cmd/tui/main.go: entry point with --server, --token, --version flags
- cmd/tui/config.go: config from ~/.config/dumpster/config.yaml or env vars
- cmd/tui/auth.go: login flow, session cookie management
- cmd/tui/api.go: HTTP client for servers, channels, messages, voice
- cmd/tui/model.go: root bubbletea model with state management
- cmd/tui/theme.go: Gruvbox dark lipgloss styles
- cmd/tui/servers.go: server bar with [D] style initials
- cmd/tui/channels.go: channel list with #text and 🔊 voice
- cmd/tui/chat.go: IRC-style message viewport with colored usernames
- cmd/tui/input.go: message input with > _ prompt
- cmd/tui/members.go: member list with ●/◐/○ status
- cmd/tui/ws.go: WebSocket client for real-time events
- cmd/tui/voice.go: voice state tracking and mute toggle
- cmd/tui/keys.go: vim-style keybindings (j/k, g/G, Tab, /, etc)
- cmd/tui/views.go: multi-pane layout rendering
- Makefile: added build-tui and run-tui targets
- go.mod/go.sum: added charmbracelet dependencies

cmd/tui/config.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	ServerURL string `yaml:"server_url"`
+	Token     string `yaml:"token"`
+}
+
+func configDir() string {
+	home, _ := os.UserHomeDir()
+	return filepath.Join(home, ".config", "dumpster")
+}
+
+func configPath() string {
+	return filepath.Join(configDir(), "config.yaml")
+}
+
+// LoadConfig loads config from file, then overlays env vars.
+func LoadConfig() (*Config, error) {
+	cfg := &Config{
+		ServerURL: "http://localhost:8080",
+	}
+
+	// Try to load from file
+	data, err := os.ReadFile(configPath())
+	if err == nil {
+		_ = yaml.Unmarshal(data, cfg)
+	}
+
+	// Env var overrides
+	if v := os.Getenv("DUMPSTER_SERVER"); v != "" {
+		cfg.ServerURL = v
+	}
+	if v := os.Getenv("DUMPSTER_TOKEN"); v != "" {
+		cfg.Token = v
+	}
+
+	return cfg, nil
+}
+
+// SaveConfig writes the config to disk.
+func SaveConfig(cfg *Config) error {
+	dir := configDir()
+	if err := os.MkdirAll(dir, 0o700); err != nil {
+		return fmt.Errorf("create config dir: %w", err)
+	}
+	data, err := yaml.Marshal(cfg)
+	if err != nil {
+		return fmt.Errorf("marshal config: %w", err)
+	}
+	return os.WriteFile(configPath(), data, 0o600)
+}