FIX 1: _content_has_local_images and extract_local_images now skip lines inside
``` fences so a local-image ref inside a code block is not treated as real.
FIX 2: md_translate.translate() tracks fence state; callout/columns/mention
transforms are suppressed for lines inside ``` ... ``` blocks (pass verbatim).
FIX 3: main() catches NtnUploadError and prints a clean error + e.stderr before
sys.exit(1); body moved to _main_body(parser, args).
FIX 4: ntn_files.upload() raises NtnUploadError on empty stdout instead of
IndexError, giving a clean message combined with FIX 3.
FIX 5: Removed unused write_to_page() (both page paths are inlined).
FIX 6: create_page_markdown() omits the 'markdown' key when value is falsy,
avoiding empty-markdown sends on DB rows created without --file/--stdin.
FIX 7: CLAUDE.md documents --allow-deleting-content scope (markdown engine only).
TDD: Added test_fence_passthrough_no_transform (md_translate, suite now 8) and
test_local_image_inside_fence_ignored (engine_routing, suite now 6).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
