[Feature]: Add SEC EDGAR Company 10-K & 10-Q Filing Search Tool (Python)

### Description Create a Python tool in `tools/sec_edgar_filings/` that searches SEC EDGAR for public company quarterly (10-Q), annual (10-K), and current (8-K) regulatory filings by stock ticker or CIK. ### Acceptance Criteria - [ ] Directory `tools/sec_edgar_filings/` with `tool.py`, `metadata.json`, `requirements.txt`, and `README.md`. - [ ] Parameters: `ticker` (string, e.g. `AAPL`), `form_type` (e.g. `10-K`, `10-Q`, `8-K`), `limit` (int, default 5). - [ ] Returns filing date, report period, form type, and direct accession URL. - [ ] Sets required SEC User-Agent header according to SEC guidelines. - [ ] Passes `python3 scripts/validate_tools.py`.