feat: ACK-based message delivery, markdown stripping, prompt fixes

- Connector: send_and_wait_ack() waits for ACK before returning
- Responder: ACK waiting for DMs with retry, delay-based for broadcasts
- Chunker: strip_markdown() removes bold/italic/headers/lists from LLM output
- Router: applies strip_markdown before chunking
- Prompt: stronger no-markdown rules, no manual continuation prompt, gateway explanation
- Config: delays 3-5s (was 2.2-3), max_length 200 (was 150), max_messages 3 (was 2)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

meshai/config.py

@@ -35,10 +35,10 @@ class ConnectionConfig:
 class ResponseConfig:
     """Response behavior settings."""
 
-    delay_min: float = 2.2
+    delay_min: float = 3.0
     delay_max: float = 3.0
-    max_length: int = 150
-    max_messages: int = 2
+    max_length: int = 200
+    max_messages: int = 3
 
 
 @dataclass
@@ -107,7 +107,9 @@ class LLMConfig:
         "the command list provided below. Don't dump lists unless asked.\n"
         "- You are part of the freq51 mesh.\n"
         "- When asked about yourself or commands, answer conversationally. Don't dump lists.\n"
-        "- You are part of the freq51 mesh in the Twin Falls, Idaho area."
+        "- You are part of the freq51 mesh in the Twin Falls, Idaho area.\n"
+        "- NEVER use markdown formatting (no bold, no asterisks, no bullet points, no numbered lists). Plain text only.\n"
+        "- NEVER say 'Want me to keep going?' -- the system handles continuation prompts automatically."
     )
     use_system_prompt: bool = True  # Toggle to disable sending system prompt
     web_search: bool = False  # Enable web search (Open WebUI feature)