ci: add GitHub Actions workflows with semantic-release auto-versioning

chore: fix all 702 clippy warnings across codebase
- auto-fix 475 via cargo clippy --fix
- fix remaining 227 manually: uninlined_format_args, redundant_closure, match_same_arms,
  underscore_binding, format_push_string, items_after_statements, needless_pass_by_value,
  clone_on_copy, case_sensitive_extension, single_match/let-else, write_with_newline,
  and other clippy lints

src/tool/utility/todofinish.rs

@@ -36,9 +36,9 @@ impl Tool for Todofinish {
         }
 
         let content = std::fs::read_to_string(&path)
-            .map_err(|e| anyhow!("failed to read todo.md: {}", e))?;
+            .map_err(|e| anyhow!("failed to read todo.md: {e}"))?;
 
-        let task_index = args.get("task_index").and_then(|v| v.as_i64());
+        let task_index = args.get("task_index").and_then(serde_json::Value::as_i64);
 
         let mut new_content = String::new();
         let mut task_count = 0;
@@ -70,10 +70,10 @@ impl Tool for Todofinish {
         }
 
         std::fs::write(&path, new_content)
-            .map_err(|e| anyhow!("failed to write to todo.md: {}", e))?;
+            .map_err(|e| anyhow!("failed to write to todo.md: {e}"))?;
 
         if let Some(idx) = task_index {
-            Ok(format!("Successfully marked task {} as finished.", idx))
+            Ok(format!("Successfully marked task {idx} as finished."))
         } else {
             Ok("Successfully marked ALL tasks as finished.".to_string())
         }