feat: add search command (CLI + DB + tests)

[raghava0071]

Summary

Adds a search command to the CLI and a DB helper so users can search applications by company, role, source, or notes.

Changes

• jobcli/db.py: add search_applications(query, limit) using SQL LIKE across fields
• jobcli/cli.py: add search subcommand + handler
• pyproject.toml: console script entry (jobcli) already added

How to test locally

# from the project root, with venv active
pytest -q
jobcli search --q "Analyst" --limit 5
# or: python -m jobcli.cli search --q "Analyst"