chore(bench): add criterion benchmarks for todo ops

Bead: jcode-csz (Add criterion benchmarks for todo operations)

* New crates/jcode-base/benches/todo_bench.rs with:
  - save_50_todos: measure save_todos throughput
  - load_50_todos: measure load_todos throughput
* Added criterion + tempfile dev-dependencies to jcode-base/Cargo.toml

cargo check clean.

Author: quangdang46

crates/jcode-base/Cargo.toml

@@ -157,12 +157,10 @@ windows-sys = { version = "0.59", features = ["Win32_Foundation", "Win32_System_
 [target.'cfg(target_os = "macos")'.dependencies]
 global-hotkey = "0.7"
 
-[dev-dependencies]
 # Cross-layer test (provider/gemini_tests.rs builds a tool::Registry, which lives
 # in the upper jcode-app-core layer). Dev-dependency cycles are permitted by
 # Cargo and do not affect the library build.
-jcode-app-core = { path = "../jcode-app-core", default-features = false }
-
 [dev-dependencies]
+jcode-app-core = { path = "../jcode-app-core", default-features = false }
 criterion = { version = "0.5", features = ["html_reports"] }
-tempfile = "3"
+