Fix Telegram Markdown formatting and clarify tool/memory distinctions

- Add escape_telegram_markdown() to handle underscores in tool names
  (e.g., build_software was breaking Telegram's Markdown parser)
- Use Telegram-compatible *bold* syntax instead of **bold**
- Clarify workspace memory vs filesystem tool descriptions to prevent
  LLM from using read_file on memory_tree paths
- Update build_software to strongly prefer Rust WASM for agent tools
- Rewrite WASM tool template to use Component Model with wit_bindgen
  instead of outdated extern "C" approach

Co-Authored-By: Claude Opus 4.5 <[email protected]>

src/agent/agent_loop.rs

@@ -2,6 +2,29 @@
 
 use std::sync::Arc;
 
+/// Escape special characters for Telegram's legacy Markdown.
+///
+/// In Telegram's Markdown mode, these characters have special meaning:
+/// - `_` starts/ends italic
+/// - `*` starts/ends bold
+/// - `` ` `` starts/ends code
+/// - `[` starts a link
+///
+/// We escape them with backslash so dynamic content doesn't break formatting.
+fn escape_telegram_markdown(s: &str) -> String {
+    let mut result = String::with_capacity(s.len());
+    for c in s.chars() {
+        match c {
+            '_' | '*' | '`' | '[' => {
+                result.push('\\');
+                result.push(c);
+            }
+            _ => result.push(c),
+        }
+    }
+    result
+}
+
 use futures::StreamExt;
 use tokio::sync::Mutex;
 use uuid::Uuid;
@@ -341,17 +364,22 @@ impl Agent {
                 } else {
                     params_preview
                 };
+                // Escape Markdown special chars in dynamic values to avoid breaking
+                // Telegram's Markdown parser (underscores, asterisks, backticks, brackets)
+                let tool_name_escaped = escape_telegram_markdown(&tool_name);
+                let description_escaped = escape_telegram_markdown(&description);
+                // Params go inside a code block, so no escaping needed there
                 Ok(Some(format!(
                     "🔒 Tool requires approval:\n\n\
-                     **Tool:** {}\n\
-                     **Description:** {}\n\
-                     **Parameters:** ```\n{}\n```\n\n\
+                     *Tool:* {}\n\
+                     *Description:* {}\n\
+                     *Parameters:*\n```\n{}\n```\n\n\
                      Reply with:\n\
-                     - `yes` or `approve` to allow this tool\n\
-                     - `always` to always allow this tool in this session\n\
-                     - `no` or `deny` to reject\n\n\
+                     • yes or approve to allow this tool\n\
+                     • always to always allow this tool in this session\n\
+                     • no or deny to reject\n\n\
                      Request ID: {}",
-                    tool_name, description, params_truncated, request_id
+                    tool_name_escaped, description_escaped, params_truncated, request_id
                 )))
             }
         }

src/agent/heartbeat.rs

@@ -244,7 +244,7 @@ impl HeartbeatRunner {
         };
 
         let response = OutgoingResponse {
-            content: format!("🔔 **Heartbeat Alert**\n\n{}", message),
+            content: format!("🔔 *Heartbeat Alert*\n\n{}", message),
             thread_id: None,
             metadata: serde_json::json!({
                 "source": "heartbeat",