[painbaba]

Summary

First TypeScript solution for the repo, as requested in #192: solutions/typescript/practice1.ts, a port of the existing Python Valid Parentheses solution (solutions/python/practice410.py) so learners can compare the two side by side.

• Same stack-based algorithm, with TypeScript type annotations on the function signature, the lookup object (Record<string, string>), the stack (string[]), and the test-case list (Array<[string, boolean]>).
• Includes 9 standalone self-checking cases (same suite as the Python version, including the empty-string and unmatched-open edge cases) — no test framework needed, just node solutions/typescript/practice1.ts.
• Brief comments explain why a stack matches the "most recent unmatched bracket" rule.

This makes TypeScript the fourth language for this problem alongside Python, JavaScript, and Java.

Related issue

Closes #192

Validation

• node solutions/typescript/practice1.ts on Windows, Node v24.17.0 (native TypeScript type-stripping): All 9 test cases passed!
• Repository header validator (python -I scripts/check_solution_headers.py --base upstream/main --head HEAD): passed.

Checklist

• The solution includes the required problem, source, and note header comment.
• The file is in the correct solutions/<language>/ folder (solutions/typescript/, new language folder, lowercase) and follows the practice<n> naming convention.
• I ran the solution and checked that it works.
• I have kept this pull request focused on one change.

[Huerte]

@painbaba Hi there! Thanks for the contribution.