Clean up stale code after get_journal() refactor
Remove dead code paths that became unreachable after get_journal() was
updated to auto-create the journal directory with platform-specific
defaults instead of raising RuntimeError.
- Remove unused load_dotenv imports from 4 files
- Remove 8 dead except RuntimeError handlers across tools/routes
- Remove stale test_entity_add_aka_runtime_error test
- Update docstrings that referenced old JOURNAL_PATH behavior
- Update AGENTS.md to recommend get_journal() over load_dotenv()
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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>