chore(release): prepare v1.2.1

Bump the package version to 1.2.1 for multiball Greifarm capture preservation and scoping fixes. Update CHANGELOG.md and refresh the tracked web WASM artifact.

Test Plan:
- `just test` -- passed (152 game tests and 8 service tests)
- `just clippy` -- passed
- `just build-production` -- passed
- `just web-build` -- passed
- `cargo +nightly fmt --all -- --check` -- passed
- `rumdl check --flavor commonmark CHANGELOG.md` -- passed
- `cargo metadata --locked --format-version 1 --no-deps` -- passed
- `git diff --cached --check` -- passed

tdkpin-rs/Cargo.lock

@@ -551,7 +551,7 @@ dependencies = [
 
 [[package]]
 name = "tdkpin-rs"
-version = "1.2.0"
+version = "1.2.1"
 dependencies = [
  "directories",
  "futures-util",