feat(cli): add modeldock verify --all

[utkarsha741]

Summary

Adds modeldock verify --all to bulk-verify every installed model,
reusing the existing ModelManager.verify() logic per model. Prints
a rich summary table (name + OK/FAILED) and supports --json output
for scripting.

Closes #41

Changes

• New verify CLI command (src/modeldock/cli/commands/verify.py),
  registered in app.py.
• render_verify() added to console.py for the summary table.
• Unit tests covering --all, explicit model names, empty-installed
  edge case, invalid flag combos, exit codes, and --json output.

Testing

• pytest -q (593 passed, 4 skipped — pre-existing Ollama skips)
• ruff format --check, mypy --strict, bandit all clean on
  changed files

Checklist

• Branch named per Git Workflow (feature/verify-all)
• Not developed on main
• Code follows AGENT.md standards (type hints, Pydantic v2, no
  generic Exception, no business logic in CLI)
• domain/ and ports/ stay pure (untouched by this change)
• Quality gates pass locally: ruff, mypy --strict, bandit, pytest
• Docs not updated (no public API/config change beyond the new
  CLI flag itself)
• pyproject.toml/__init__.py versions unchanged (not a release)