Fix TypeScript template test discovery for Node 20

[GsCommand]

Motivation

• Node 20 does not export globSync and passing wildcard patterns to node --test is unreliable, so test discovery should explicitly locate test files and skip missing optional suites.

Description

• Replace glob/wildcard invocation with directory-based discovery in typescript-sdk/scripts/template-tests.mjs using existsSync, readdirSync, path, and fileURLToPath to collect *.test.mjs files and invoke node --test with explicit file paths.
• Skip suites when the directory is absent or no test files match, and run tests with cwd set to the repository root.

Testing

• Ran cd typescript-sdk && npm run typecheck && npm run build && npm run test:unit, which failed at existing src/index.ts TypeScript errors so the build/tests did not complete.
• Ran node scripts/parity-check.mjs, which failed because TypeScript build artifacts are absent when the build fails.

---

Codex Task