🐛 Bug Description

When Telegram message sending fails due to network errors (e.g., "httpx.ConnectError"), the failure is silently logged but not surfaced to the user. This creates a confusing UX where the user thinks the agent has "hung" or "crashed", when in fact the response was generated but failed to deliver.

Real-world Impact

• User waited 1+ hour for a response that was already generated but failed to send
• User eventually sent "?卡住了？" ("Hung?") because no feedback was provided
• The agent had actually responded within seconds, but the user never received it

📋 Reproduction Steps

1. Start a conversation with Hermes via Telegram
2. Trigger a network interruption during response delivery (e.g., transient connectivity issue)
3. Observe that:
   • Agent generates response (visible in logs)
   • "[Telegram] Sending response..." appears in logs
   • "[Telegram] Failed to send response: httpx.ConnectError" is logged
   • User receives no notification of the failure
   • User sees no retry attempt

📜 Log Evidence

From ~/.hermes/logs/gateway.log:

# Response was generated and attempt was made to send
2026-03-25 09:50:19,203 INFO gateway.platforms.base: [Telegram] Sending response (222 chars) to 5570584365

# But connection failed
[Telegram] Failed to send response: httpx.ConnectError: 

From session transcript, the response was generated at 08:45:37 but user received nothing until asking at 09:50:19 (1+ hour later).

🔍 Root Cause Analysis

In gateway/platforms/telegram.py (and likely other adapters), when send() fails:

1. Exception is caught and logged
2. No retry mechanism is triggered
3. No user notification is sent
4. The failure is effectively silent from user's perspective

💡 Proposed Solutions

Option A: Automatic Retry with Exponential Backoff

• Retry failed sends 2-3 times with exponential backoff
• Only surface failure to user after retries exhausted

Option B: Immediate User Notification

• If send fails, immediately notify user:
  "⚠️ Message delivery failed. Retrying..."
• Then retry or offer manual retry command

Option C: Queue for Later Delivery

• Store failed sends in a retry queue
• Attempt redelivery when connection recovers
• Notify user of queued messages

🎯 Priority

Medium-High — This significantly degrades UX and can cause users to abandon sessions thinking the service is broken.

📝 Environment

• Hermes Agent version: Latest (commit 2233f76)
• Platform: Telegram
• Python: 3.11
• OS: macOS (from logs)

Related Issues

This may be related to general gateway reliability improvements and error handling enhancements.