feat: Tier 3-4 — communication channels & productivity skills

Communication channels:
- Telegram bot (long polling, no external deps, net/http only)
  - Bidirectional messaging with typing indicators
  - Chat ID allowlist for security
  - Auto-retry on Markdown parse failures
  - Message chunking for >4096 char responses
  - /start and /health commands
- Webhook endpoint (POST /api/webhooks)
  - HMAC-SHA256 signature verification (GitHub compatible)
  - Sync and async modes
  - Plain text fallback for non-JSON payloads
- Email notifications (net/smtp, no external deps)
  - SMTP sender with configurable host/port/auth
  - send_email skill for agent-initiated emails

Productivity skills:
- Task management: task_add, task_list, task_update, task_delete
  - JSON file storage, priority sorting, tag filtering
  - Status tracking (todo/in_progress/done)
- Note-taking/PKM: note_save, note_read, note_list, note_delete, note_search
  - Markdown files in data/notes/
  - Full-text search with snippet extraction
  - Path traversal protection via sanitization

Config additions:
- WebhookChannelConfig (enabled, HMAC secret)
- EmailConfig (SMTP host/port/username/password/from)
- Env var resolution for webhook secret and email password

Zero new external dependencies — all implemented with Go stdlib.

Author: mandarl

cmd/pennyclaw/main.go

@@ -12,7 +12,9 @@ import (
 	"syscall"
 
 	"github.com/mandarl/pennyclaw/internal/agent"
+	"github.com/mandarl/pennyclaw/internal/channels/telegram"
 	"github.com/mandarl/pennyclaw/internal/channels/web"
+	"github.com/mandarl/pennyclaw/internal/channels/webhook"
 	"github.com/mandarl/pennyclaw/internal/config"
 )
 
@@ -74,22 +76,49 @@ func main() {
 		log.Fatalf("Failed to initialize agent: %v", err)
 	}
 
+	// Create webhook handler (used by web server if enabled)
+	var webhookHandler *webhook.Handler
+	if cfg.Channels.Webhook.Enabled {
+		webhookHandler = webhook.New(webhook.Config{
+			Secret: cfg.Channels.Webhook.Secret,
+		}, ag.HandleMessage)
+		log.Println("Webhook endpoint enabled at /api/webhooks")
+	}
+
 	// Start web server
 	srv := web.NewServer(cfg.Server.Host, cfg.Server.Port, ag.HandleMessage, cfg, *configPath,
-		ag.Memory(), version, ag.Workspace(), ag.Scheduler(), ag.SkillPack())
+		ag.Memory(), version, ag.Workspace(), ag.Scheduler(), ag.SkillPack(), webhookHandler)
 	go func() {
 		log.Printf("PennyClaw %s starting on %s:%d", version, cfg.Server.Host, cfg.Server.Port)
 		if err := srv.Start(); err != nil {
 			log.Fatalf("Web server error: %v", err)
 		}
 	}()
 
+	// Start Telegram bot if configured
+	var tgBot *telegram.Bot
+	if cfg.Channels.Telegram.Enabled && cfg.Channels.Telegram.Token != "" {
+		tgBot, err = telegram.New(telegram.Config{
+			Token: cfg.Channels.Telegram.Token,
+		}, ag.HandleMessage)
+		if err != nil {
+			log.Printf("Warning: failed to create Telegram bot: %v", err)
+		} else {
+			if err := tgBot.Start(); err != nil {
+				log.Printf("Warning: failed to start Telegram bot: %v", err)
+			}
+		}
+	}
+
 	// Graceful shutdown
 	sigCh := make(chan os.Signal, 1)
 	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
 	<-sigCh
 
 	log.Println("Shutting down PennyClaw...")
+	if tgBot != nil {
+		tgBot.Stop()
+	}
 	ag.Stop()
 	srv.Stop()
 	log.Println("Goodbye!")

internal/agent/agent.go

@@ -14,6 +14,7 @@ import (
 	"github.com/mandarl/pennyclaw/internal/cron"
 	"github.com/mandarl/pennyclaw/internal/llm"
 	"github.com/mandarl/pennyclaw/internal/memory"
+	"github.com/mandarl/pennyclaw/internal/notify"
 	"github.com/mandarl/pennyclaw/internal/sandbox"
 	"github.com/mandarl/pennyclaw/internal/skillpack"
 	"github.com/mandarl/pennyclaw/internal/skills"
@@ -110,6 +111,24 @@ func New(cfg *config.Config, dataDir string) (*Agent, error) {
 	// Register workspace skills
 	agent.registerWorkspaceSkills()
 
+	// Register productivity skills (tasks, notes)
+	skills.RegisterProductivitySkills(skillRegistry, dataDir)
+
+	// Register email skill if configured
+	var emailNotifier *notify.EmailNotifier
+	if cfg.Email.Enabled {
+		emailNotifier = notify.NewEmailNotifier(notify.EmailConfig{
+			SMTPHost:    cfg.Email.SMTPHost,
+			SMTPPort:    cfg.Email.SMTPPort,
+			Username:    cfg.Email.Username,
+			Password:    cfg.Email.Password,
+			FromAddress: cfg.Email.FromAddress,
+			FromName:    cfg.Email.FromName,
+		})
+		skills.RegisterEmailSkill(skillRegistry, emailNotifier)
+		log.Printf("Email notifications enabled (SMTP: %s)", cfg.Email.SMTPHost)
+	}
+
 	// Initialize cron scheduler (uses same SQLite DB)
 	scheduler, err := cron.NewScheduler(mem.DB(), agent.HandleMessage)
 	if err != nil {