fix: harden TypeScript project and async detection

[GDownes]

Problems

1. Running desloppify scan --path libs/cognito-deploy-contracts in a TypeScript monorepo creates tsconfig.desloppify.json at the repository root with a hard-coded extends: ./tsconfig.app.json. Library projects commonly own tsconfig.json instead, so the unused detector type-checks the wrong project or falls back after a timeout.
2. The async_no_await smell detector treats the first { in a multiline typed parameter as the function body. It therefore flags async declarations that contain direct await expressions whenever their argument uses an inline object type.

Fixes

• Locate the nearest owning tsconfig.app.json or tsconfig.json, create the temporary override beside it, and extend that config. If no TypeScript config exists, use the existing source-based fallback directly.
• Parse the complete parameter list before locating an async declaration body, including multiline inline-object parameters and return types, then inspect the real body for await.
• Add regression coverage for both defects.

Validation

• pytest desloppify/languages/typescript/tests/test_ts_unused.py -q — 19 passed
• pytest desloppify/languages/typescript/tests/ -q — 429 passed
• Focused async smell helper suite — 89 passed
• python -m pytest desloppify/tests/ -q — 5651 passed, 153 skipped, 3 unrelated Bash failures
• The same 3 Bash failures reproduce without these changes
• Verified against WorkOrderGuard: library-local TypeScript config resolution works, and false async_no_await findings fell from 10 to 0