docs(pdftract-nf172): add coordinator verification note

Add verification note for Phase 3.5 Inline Image skip coordinator.
All 3 children closed, all acceptance criteria PASS.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

notes/pdftract-nf172.md

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+# pdftract-nf172: Phase 3.5 Inline Image skip (coordinator)
+
+## Summary
+
+Coordinator bead for Phase 3.5: detect and skip BI/ID/EI inline image sequences in content streams. All 3 children have been completed and the inline image parsing functionality is fully implemented.
+
+## Children Completed
+
+All 3 children are CLOSED:
+- **pdftract-1sxpa**: BI/ID inline image header parser - CLOSED (commit 4ac8479)
+- **pdftract-1f0cj**: ID-to-EI raw-bytes scanner with whitespace-preceded EI detection - CLOSED
+- **pdftract-axcri**: Inline image -> ImageXObject record in page image list - CLOSED
+
+## Acceptance Criteria Verification
+
+| Criterion | Status | Evidence |
+|-----------|--------|----------|
+| All 3 children closed | **PASS** | `bf show` confirms all 3 children are closed |
+| Inline image followed by text operators parsed correctly | **PASS** | `parse_inline_image()` in render.rs advances lexer past EI; subsequent tokens parse normally |
+| Embedded "EI" bytes not treated as terminator | **PASS** | Test `test_scan_inline_image_data_with_embedded_ei` passes - input `b"ABCDEI\nEI"` correctly returns `b"ABCDEI"` (inner EI not preceded by ws) |
+
+## Implementation Overview
+
+The inline image implementation works as follows:
+
+1. **Header parsing** (pdftract-1sxpa): `parse_inline_image_header()` parses BI...ID dictionary with shorthand key expansion
+2. **Data scanning** (pdftract-1f0cj): `scan_inline_image_data()` byte-by-byte scan for whitespace-preceded EI
+3. **ImageXObject recording** (pdftract-axcri): `collect_image_xobjects()` records both XObject and inline images with CTM-derived bbox
+
+## Test Results
+
+All 14 inline_image tests pass:
+- `test_scan_inline_image_data_basic` - Basic BI...ID...EI parsing
+- `test_scan_inline_image_data_with_embedded_ei` - EI in data not preceded by ws
+- `test_scan_inline_image_data_empty` - Empty image
+- `test_scan_inline_image_data_no_ei` - No terminator handling
+- `test_scan_inline_image_data_various_whitespace` - All 6 ws bytes before EI
+- `test_scan_inline_image_data_binary_content` - Binary data with 0x45/0x49 bytes
+- `test_scan_inline_image_data_lexer_position` - Lexer advancement verification
+- `test_parse_basic_header` - Basic header parsing
+- `test_shorthand_expansion` - Shorthand key expansion
+- `test_id_whitespace_validation` - ID whitespace requirement
+- `test_parse_header_with_array_filter` - Array filter chains
+- `test_parse_header_with_missing_value` - Malformed header recovery
+- `test_inline_image_header_new` - Header construction
+- `test_inline_image_header_has_required_fields` - Field presence
+
+## Integration with Content Stream Parser
+
+The `collect_image_xobjects()` function in `render.rs` integrates inline image parsing into the content stream interpreter:
+- BI keyword triggers `parse_inline_image()` which consumes the entire BI/ID/EI sequence
+- Lexer is positioned after EI, allowing subsequent text operators to parse correctly
+- ImageXObject entries are added to page image list for Phase 4.4 figure detection
+
+## Known Limitations
+
+Per the plan's "Critical considerations":
+- The whitespace-EI heuristic may terminate early if compressed image data contains `<ws>EI` (rare)
+- A more robust solution would compute expected byte length from width/height/bpc/colorspace (deferred to v0.2.0+)
+
+## References
+
+- Plan section: Phase 3.5 Inline Images (lines 1592-1600)
+- ISO 32000-1 sec 8.9.7