fix: update stale messenger_type strings after chat-system migration

- streaming.rs: Change 'teams' to 'msteams' and 'google_chat' to
  'googlechat' in recommended_strategy() to match chat-system's
  messenger_type() return values. Without this fix, Teams and Google
  Chat fall through to the default BufferAll strategy instead of
  the intended EditInPlace strategy.

- messenger_handler.rs: Add 'msteams' and 'googlechat' arms to
  get_platform_formatting_guide() so Teams and Google Chat messages
  get platform-specific formatting guidance instead of the generic
  default.

Co-Authored-By: Erica Stith <rexlunae@gmail.com>

Author: devin-ai-integration[bot]

crates/rustyclaw-core/src/gateway/messenger_handler.rs

@@ -1008,6 +1008,22 @@ fn get_platform_formatting_guide(messenger_type: &str) -> String {
 - Links: <https://url|display text>\n\
 - Use emoji reactions when appropriate".to_string(),
 
+        "msteams" => "\
+### Formatting (Microsoft Teams)\n\
+- **Markdown supported**: bold, italic, code, links, lists\n\
+- Tables render in Teams clients\n\
+- Code blocks with syntax highlighting\n\
+- Adaptive Cards supported for rich content\n\
+- Keep messages concise for readability".to_string(),
+
+        "googlechat" => "\
+### Formatting (Google Chat)\n\
+- **Basic markdown**: bold, italic, code, links\n\
+- **NO tables** — use bullet lists instead\n\
+- Code blocks supported\n\
+- Thread replies supported — prefer threading for related messages\n\
+- Keep messages concise".to_string(),
+
         "signal" => "\
 ### Formatting (Signal)\n\
 - **NO formatting support** — plain text only\n\

crates/rustyclaw-core/src/messengers/streaming.rs

@@ -270,7 +270,7 @@ pub fn recommended_strategy(messenger_type: &str) -> StreamStrategy {
     match messenger_type {
         "telegram" | "discord" | "slack" => StreamStrategy::EditInPlace,
         "irc" | "webhook" => StreamStrategy::Chunked,
-        "teams" | "google_chat" => StreamStrategy::EditInPlace,
+        "msteams" | "googlechat" => StreamStrategy::EditInPlace,
         "imessage" => StreamStrategy::BufferAll,
         _ => StreamStrategy::BufferAll,
     }