- Created install_shed_repos_for_workflow_id() to install tools from already-imported workflows
- Updated _install_workflow() to install tools when --shed_install is enabled for TRS workflows
- Fetches workflow definition from Galaxy, extracts tool requirements using ephemeris
- Installs tools from toolshed using same mechanism as local workflows
- Handles both install_repositories and update_repositories if install_most_recent_revision is set

The parse_trs_id() function had incorrect logic for determining whether
path components are workflow names or versions:

- For 5-part IDs (workflow/github.com/org/repo/main), the 5th part is
  the workflow name, not a version
- For 6-part IDs (workflow/github.com/org/repo/main/v1.0), the 6th part
  is the version
- For 7-part IDs with "versions" keyword (workflow/.../main/versions/v1.0),
  correctly recognize "versions" as a keyword and extract the actual version

This fixes all 4 failing tests in test_trs_id.py

Galaxy validates TRS URLs with a regex that requires the format:
  https://.../ga4gh/trs/v2/tools/{tool_id}/versions/{version_id}

Changed parse_trs_id() to always provide a version:
- When version is explicitly specified, use it
- When fetching from Dockstore API succeeds, use the first version
- When API fails or returns no versions, use workflow_name as default
  (e.g., "main") or "main" if no workflow_name

Updated test_parse_trs_id_version_fetch_failure to expect the new
behavior where we always include /versions/{default_version}.

This fixes the RequestParameterInvalidException error in Galaxy.

Changed from galaxy-workflow-dockstore-example-3 (which doesn't exist)
to galaxy-workflow-dockstore-example-1/mycoolworkflow (which does exist).

The new workflow:
- Exists on Dockstore at the TRS endpoint
- Has a "master" version that can be fetched
- Should work correctly with Galaxy's TRS import

- Add @pytest.mark.skipif decorator to skip test_run_trs_id on Galaxy
  release_22.05, which doesn't support TRS import
- Fix black formatting issue in test_trs_id.py by splitting long
  assertion across multiple lines

Applied improvements from code review (parts 1-3, excluding part 4):

Part 1: HTTP Fixtures for Dockstore API
- Add responses>=0.23.0 test dependency
- Create fixture directory: tests/fixtures/dockstore/
- Record real Dockstore API responses to JSON fixtures
- Refactor tests to use @responses.activate instead of mocks
- Replace mock objects with real HTTP fixtures

Part 2: TrsImporter Protocol (Dependency Injection)
- Add TrsImporter Protocol for type safety
- Create GalaxyTrsImporter implementation for Galaxy API
- Create FakeTrsImporter for testing without Galaxy
- Refactor import_workflow_from_trs to use Protocol
- Update call sites to use GalaxyTrsImporter
- Replace mock-based tests with state verification

Part 3: Fix translate_alias Tests
- Remove @patch decorators for translate_alias
- Use real PlanemoCliContext with tmp_path
- Eliminate mock objects in integration tests
- Use planemo_directory instead of workspace property

Benefits:
- Tests use real objects with controlled inputs
- Fakes record state instead of using mocks
- HTTP responses are recorded from actual API
- Better dependency injection pattern
- More maintainable test code