fix: address critical/high audit findings across WASM sub-crates

- Telegram: remove .unwrap() panic on workspace_read (owner_id check)
- WhatsApp: use configured api_version instead of hardcoded v18.0
- WhatsApp: log config parse errors before falling back to defaults
- Slack: log serialization errors in emit_message and json_response
- Google Docs: safe array access for batch update replies
- Google Sheets: safe array access for add_sheet replies
- Google Calendar: fix doc comment secret name mismatch
- Gmail: avoid unnecessary String allocation in UNREAD check

Co-Authored-By: Claude Opus 4.6 <[email protected]>

tools-src/gmail/src/api.rs

@@ -136,7 +136,7 @@ fn parse_message(v: &serde_json::Value) -> Message {
         date: get_header(payload, "Date"),
         body: extract_body(payload),
         snippet: v["snippet"].as_str().unwrap_or("").to_string(),
-        is_unread: label_ids.contains(&"UNREAD".to_string()),
+        is_unread: label_ids.iter().any(|l| l == "UNREAD"),
         label_ids,
     }
 }
@@ -198,7 +198,7 @@ pub fn list_messages(
                     to: get_header(payload, "To"),
                     date: get_header(payload, "Date"),
                     snippet: msg["snippet"].as_str().unwrap_or("").to_string(),
-                    is_unread: label_ids.contains(&"UNREAD".to_string()),
+                    is_unread: label_ids.iter().any(|l| l == "UNREAD"),
                     label_ids,
                 });
             }