feat(watcher): Phase 2.1 — SessionWatcher goroutine

- internal/watcher: detecte fin de tache via signal file, prompt ❯, idle timeout
- state: ForEachWorking, SetStalled, SetActiveAccount, ActiveAccount
- config: WatcherConfig, DispatcherConfig, JanitorConfig, NotificationsConfig + defaults
- 5 tests unitaires, go test ./... -race OK

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/config/config.go

@@ -13,11 +13,15 @@ import (
 
 // Config is the top-level configuration structure, mapping config.example.yaml.
 type Config struct {
-	Accounts   []AccountConfig  `yaml:"accounts"`
-	Pool       PoolConfig       `yaml:"pool"`
-	Quota      QuotaConfig      `yaml:"quota"`
-	Checkpoint CheckpointConfig `yaml:"checkpoint"`
-	MCPHTTP    MCPHTTPConfig    `yaml:"mcp_http"`
+	Accounts      []AccountConfig     `yaml:"accounts"`
+	Pool          PoolConfig          `yaml:"pool"`
+	Quota         QuotaConfig         `yaml:"quota"`
+	Checkpoint    CheckpointConfig    `yaml:"checkpoint"`
+	MCPHTTP       MCPHTTPConfig       `yaml:"mcp_http"`
+	Notifications NotificationsConfig `yaml:"notifications"`
+	Dispatcher    DispatcherConfig    `yaml:"dispatcher"`
+	Watcher       WatcherConfig       `yaml:"watcher"`
+	Janitor       JanitorConfig       `yaml:"janitor"`
 }
 
 // AccountConfig describes a single Anthropic account available to the daemon.
@@ -71,9 +75,38 @@ type CheckpointConfig struct {
 
 // MCPHTTPConfig defines the HTTP control-plane endpoint.
 type MCPHTTPConfig struct {
-	Listen          string `yaml:"listen"`
-	BearerTokenEnv  string `yaml:"bearer_token_env"`
-	EnableTrigger   bool   `yaml:"enable_trigger"`
+	Listen         string `yaml:"listen"`
+	BearerTokenEnv string `yaml:"bearer_token_env"`
+	EnableTrigger  bool   `yaml:"enable_trigger"`
+}
+
+// NotificationsConfig holds environment variable names for alert credentials.
+// Actual secrets are read from env at runtime — never stored in config files.
+type NotificationsConfig struct {
+	TelegramTokenEnv  string `yaml:"telegram_token_env"`
+	TelegramChatIDEnv string `yaml:"telegram_chat_id_env"`
+	ResendAPIKeyEnv   string `yaml:"resend_api_key_env"`
+	NotifyEmailEnv    string `yaml:"notify_email_env"`
+}
+
+// DispatcherConfig controls the task dispatcher behaviour.
+type DispatcherConfig struct {
+	ProjectsDir        string   `yaml:"projects_dir"`
+	IdleTimeout        Duration `yaml:"idle_timeout"`
+	PromptTimeout      Duration `yaml:"prompt_timeout"`
+	MaxDispatchPerTask int      `yaml:"max_dispatch_per_task"`
+}
+
+// WatcherConfig controls the session watcher behaviour.
+type WatcherConfig struct {
+	Interval      Duration `yaml:"interval"`
+	DoneSignalDir string   `yaml:"done_signal_dir"`
+	IdleTimeout   Duration `yaml:"idle_timeout"`
+}
+
+// JanitorConfig controls the periodic housekeeping goroutine.
+type JanitorConfig struct {
+	Interval Duration `yaml:"interval"`
 }
 
 // Duration is a time.Duration that unmarshals from YAML strings like "30s", "1h".
@@ -138,6 +171,27 @@ func (c *Config) defaults() {
 	if c.Pool.Autonomous.Max == 0 {
 		c.Pool.Autonomous.Max = 10
 	}
+	if c.Watcher.Interval.Duration == 0 {
+		c.Watcher.Interval.Duration = 30 * time.Second
+	}
+	if c.Watcher.IdleTimeout.Duration == 0 {
+		c.Watcher.IdleTimeout.Duration = 60 * time.Minute
+	}
+	if c.Watcher.DoneSignalDir == "" {
+		c.Watcher.DoneSignalDir = "/tmp"
+	}
+	if c.Janitor.Interval.Duration == 0 {
+		c.Janitor.Interval.Duration = 5 * time.Minute
+	}
+	if c.Dispatcher.IdleTimeout.Duration == 0 {
+		c.Dispatcher.IdleTimeout.Duration = 60 * time.Minute
+	}
+	if c.Dispatcher.PromptTimeout.Duration == 0 {
+		c.Dispatcher.PromptTimeout.Duration = 30 * time.Second
+	}
+	if c.Dispatcher.MaxDispatchPerTask == 0 {
+		c.Dispatcher.MaxDispatchPerTask = 3
+	}
 }
 
 // Load reads the YAML file at path, expands home paths, and applies defaults.