feat: add assistant bot with LLM integration and configuration

- Implemented the assistant bot with basic command handling and LLM routing.
- Created configuration file for the assistant bot with personality, behavior, and LLM settings.
- Added system prompt for the assistant bot to define its capabilities and limitations.
- Developed registration script for creating Matrix bot users via Synapse admin API.
- Introduced common development scripts for agent management (start, stop, list, logs).
- Scaffolded new agent creation script to streamline the addition of new agents.
- Implemented agent removal script to disable agents without deleting data.

internal/config/loader.go

@@ -29,6 +29,24 @@ func Load(path string) (*AgentConfig, error) {
 	return &cfg, nil
 }
 
+// LoadMeta reads only the `agent:` block from a config file without expanding
+// env vars or running full validation. Used by agentctl list to show all
+// agents regardless of whether their env vars are configured.
+func LoadMeta(path string) (*AgentConfig, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("read config %s: %w", path, err)
+	}
+	var cfg AgentConfig
+	if err := yaml.Unmarshal(data, &cfg); err != nil {
+		return nil, fmt.Errorf("parse config %s: %w", path, err)
+	}
+	if cfg.Agent.ID == "" {
+		return nil, fmt.Errorf("agent.id is required")
+	}
+	return &cfg, nil
+}
+
 // validate applies basic sanity checks.
 func validate(cfg *AgentConfig) error {
 	if cfg.Agent.ID == "" {