feat: Implement lesson generation feature and update status display

- Added functionality to generate lessons based on code reviews, including prompts and instructions for the reviewer.
- Updated the `.gitignore` to exclude lesson documentation files.
- Removed the `/lesson` command from the help menu and command parsing.
- Enhanced the status bar to display a message when a lesson is being generated.
- Introduced a new `lesson_running` state to track lesson generation progress.
- Updated various components to handle the new lesson generation workflow, including subagent events and token usage tracking.

src/dto/chat/tool.rs

@@ -134,7 +134,7 @@ pub struct ToolFunction {
 /// LIFO stack for `{`/`[` → append missing `"`, `]`, `}` in the right
 /// (reverse nesting) order.
 ///
-/// Why: LLM output can be cut off mid‑JSON (max_tokens hit, connection
+/// Why: LLM output can be cut off mid‑JSON (`max_tokens` hit, connection
 /// drop).  This gives tools a chance to act on whatever was emitted.
 ///
 /// Why LIFO vs. depth counters: `{` inside `[` must close with `}` before
@@ -205,29 +205,42 @@ fn repair_json(s: &str) -> String {
 pub fn sanitize_tool_arguments(args: &Value) -> Value {
     match args {
         Value::String(s) => {
-            match serde_json::from_str::<Value>(s) {
-                Ok(v) => v,
-                Err(e) => {
-                    // Try to repair truncated JSON before giving up.
-                    let repaired = repair_json(s);
-                    match serde_json::from_str::<Value>(&repaired) {
-                        Ok(v) => {
-                            tracing::warn!(
-                                "tool argument string was truncated — repaired \
-                                 successfully: {}",
-                                e,
-                            );
-                            v
-                        }
-                        Err(e2) => {
-                            tracing::error!(
-                                "tool argument is a JSON string but failed to parse: {} \
-                                 (after repair: {}). Wrapping in object. Raw (first 200): {}",
-                                e, e2, s.chars().take(200).collect::<String>(),
-                            );
-                            serde_json::json!({"_raw": s, "_parse_error": e.to_string()})
-                        }
-                    }
+            // Attempt 1: direct parse.
+            if let Ok(v) = serde_json::from_str::<Value>(s) {
+                return v;
+            }
+            // Attempt 2: strip control chars (0x00-0x1F except \t, \n)
+            // that some LLM providers emit as literal bytes in JSON strings
+            // (e.g. multi-line commit messages), then retry.
+            let cleaned: String = s.chars()
+                .filter(|&c| !c.is_control() || c == '\t' || c == '\n' || c == '\r')
+                .collect();
+            if cleaned.len() != s.len() {
+                if let Ok(v) = serde_json::from_str::<Value>(&cleaned) {
+                    tracing::warn!(
+                        "tool argument contained control characters — stripped \
+                         and reparsed successfully",
+                    );
+                    return v;
+                }
+            }
+            // Attempt 3: repair truncated JSON and retry.
+            let input = if cleaned.len() == s.len() { s } else { &cleaned };
+            let repaired = repair_json(input);
+            match serde_json::from_str::<Value>(&repaired) {
+                Ok(v) => {
+                    tracing::warn!(
+                        "tool argument string was truncated — repaired successfully",
+                    );
+                    v
+                }
+                Err(e2) => {
+                    tracing::error!(
+                        "tool argument is a JSON string but failed to parse. \
+                         Wrapping in object. Error: {}. Raw (first 200): {}",
+                        e2, s.chars().take(200).collect::<String>(),
+                    );
+                    serde_json::json!({"_raw": s, "_parse_error": e2.to_string()})
                 }
             }
         }