fix: resolve 15 test failures on Windows platform

[rubuslab]

Fixes test suite failures when running on Windows (win32) due to
platform-specific behaviors not being properly handled.

Source code fixes:

• src/openharness/swarm/team_lifecycle.py: Use Path.replace() instead of Path.rename() for atomic file writes, as rename() raises FileExistsError on Windows when the target already exists
• src/openharness/autopilot/service.py: Use posix=False for shlex.split() on Windows to handle backslash paths correctly
• src/openharness/ui/input.py: Lazily initialize PromptSession to avoid NoConsoleScreenBufferError when no Windows console is attached
• pyproject.toml: Add tzdata dependency for timezone support on Windows (where system timezone data is not available to Python's zoneinfo)

Test fixes:

• tests/test_ohmo/test_gateway.py: Mock Windows-specific process management (wmic + taskkill) instead of POSIX-only (ps + os.kill); replace deprecated datetime.utcnow() with datetime.now(UTC)
• tests/test_swarm/test_lockfile.py: Skip POSIX-only fcntl test on Windows
• tests/test_swarm/test_registry.py: Use explicit InProcessBackend registration instead of monkeypatch to avoid module cache invalidation from test_imports.py
• tests/test_tools/test_bash_tool.py: Use monkeypatch.setitem on function globals to correctly mock imported create_shell_subprocess
• tests/test_utils/test_shell.py: Mock get_platform() to ensure consistent shell binary expectations across platforms

Summary

• Fix 15 test failures and resolve lint issues when running the test suite on Windows (win32).
• Bug fixed in tests.

Validation

• uv run ruff check src tests scripts
• uv run pytest -q
• cd frontend/terminal && npx tsc --noEmit (if frontend touched)

Notes

• Related issue:
• Follow-up work:

[rubuslab]

Before the fix, run test cmd "uv run pytest -q" on Windows.The test results show 15 failures.

[rubuslab]

After fix, all tests passed on Windows.