The similarity cache build was failing because parse_theme_tags() was checking isinstance(tags, list) but Parquet files return numpy.ndarray objects. This caused all cards to be flagged as having no theme tags, resulting in an empty cache.
Changed to use hasattr(__len__) check instead, which works for both lists and numpy arrays.
- Add ensure_theme_tags_list() utility to builder_utils for simpler numpy array handling
- Update phase3_creatures.py: 6 locations now use bu.ensure_theme_tags_list()
- Update phase4_spells.py: 9 locations now use bu.ensure_theme_tags_list()
- Update tagger.py: 2 locations use hasattr/list() for numpy compatibility
- Update extract_themes.py: 2 locations use hasattr/list() for numpy compatibility
- Fix build-similarity-cache.yml verification script to handle numpy arrays
- Enhance workflow debug output to show complete row data
Parquet files return numpy.ndarray objects for array columns, not Python lists.
The M4 migration added numpy support to canonical parse_theme_tags() in builder_utils,
but many parts of the codebase still used isinstance(list) checks that fail with arrays.
This commit systematically replaces all 19 instances with proper numpy array handling.
Fixes GitHub Actions workflow 'RuntimeError: No theme tags found' and verification failures.
- Fix KeyError in generate_theme_catalog.py: use isCommander column correctly
- DataFrame.get() doesn't work like dict.get() - use column name directly
- Enhanced debug step to print full row data for better diagnostics
document deck summary DFC badges, exporter annotations, and per-face metadata across README/DOCKER/release notes
record completion of all MDFC roadmap follow-ups and add the authoring guide for multi-face CSV entries
wire in optional DFC_PER_FACE_SNAPSHOT env support, exporter regression tests, and diagnostics updates noted in the changelog
- reuse shared hover metadata in Step 5 and keep the preview in-app\n- let hover reasons expand without an embedded scrollbar\n- document the hover polish in CHANGELOG and release notes
