fix: parse multiline TypeScript function bodies

[treygoff24]

Problem

The TypeScript async_no_await smell detector can report false positives for multiline async functions whose signatures contain braces before the function body, such as:

• default object parameters (opts = {})
• destructured parameters
• return type object literals inside generics (Promise<{ ... }>)

The previous body extractor picked the first { within the signature window, so it inspected an empty/default/destructuring/type block instead of the real function body and missed real await expressions.

Fix

• Find the actual function body brace while ignoring braces inside parameter lists and return-type syntax.
• Reuse the existing block-end scanner once the body brace is found.
• Add regressions for multiline exported async signatures and destructured parameters with Promise<{ ... }> return types.

Verification

• uvx pytest desloppify/languages/typescript/tests/smells/test_ts_smell_helpers.py::TestDetectAsyncNoAwait desloppify/languages/typescript/tests/test_ts_smells.py::test_detect_async_no_await desloppify/languages/typescript/tests/test_ts_smells.py::test_async_with_await_not_flagged -q — passed
• uvx pytest desloppify/languages/typescript/tests -q — passed, 428 tests
• uvx ruff check desloppify/languages/typescript/detectors/smells/detector_core.py desloppify/languages/typescript/tests/smells/test_ts_smell_helpers.py — passed
• Verified against /Users/treygoff/Code/elevenlabs-cli with PYTHONPATH=/tmp/desloppify-fix ... python -m desloppify scan --path .; false async/no-await findings dropped and objective score improved.

Note: uvx pytest desloppify/tests/ -q currently has 3 unrelated failures in desloppify/tests/lang/common/test_bash_unused_imports.py (bash source/dot-source unused import expectations returned no findings). These are unrelated to this TypeScript detector change.