This PR upgrades project dependencies to current versions (while intentionally keeping zod unchanged), aligns test configuration with the latest Vitest behavior, and updates a few test cleanup patterns to keep the suite stable. No production feature logic was changed.

What changed

• Upgraded runtime dependencies, including Turf packages and Winston.
• Upgraded dev/tooling dependencies, notably:
  • Vitest and coverage plugin to v4
  • TypeScript to v6
  • LangGraph and related LangChain packages
  • Node type definitions and Supertest
• Adjusted test runner config to match newer Vitest options for process args and fork settings.
• Replaced restoreAllMocks() with clearAllMocks() in affected tests to avoid over-resetting mocked implementations under the upgraded stack.
• Regenerated lockfile accordingly.

Why

• Keep dependencies up to date for security, compatibility, and maintenance.
• Prevent regressions caused by breaking/changed behavior in newer Vitest/tooling versions.
• Preserve existing test expectations with minimal behavioral changes.

Risk / impact

• Low to medium: mostly tooling and test-layer impact.
• Application runtime behavior is expected to remain unchanged.
• Main risk is subtle test-environment differences from Vitest v4 / TypeScript v6.

Validation

• Targeted unit test execution passed (urbanisme suite).
• Additional full-suite CI validation is recommended after merge.