refactor(vector): address PR #775 review round 3 — fix unused var, harden boundary lookup, rename trace span

- pdf_highlighter.compute_chunk_bboxes_batch: drop unused chunk_text
  destructure (SonarQube finding), and replace positional
  page_boundaries[page_num - 1] with a key-based next() match so
  reordered or non-1-indexed boundaries can't silently shift the bbox.
  Convert touched f-string log to lazy %s formatting.
- vector/processor: rename the trace_operation span from
  "vector_sync.generate_highlights" to "vector_sync.compute_chunk_bboxes"
  to match what the function actually does.
- Add test_compute_chunk_bboxes_handles_unordered_page_boundaries —
  reverses the boundaries list and asserts identical results to the
  in-order case, guarding the boundary-lookup regression class.
- Pin pre-push-review skill to sonnet model.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

nextcloud_mcp_server/search/pdf_highlighter.py

@@ -739,17 +739,26 @@ class PDFHighlighter:
                 start_offset,
                 end_offset,
                 _,
-                chunk_text,
+                _,
             ) in chunks:
                 chunk_page_info = PDFHighlighter.find_chunk_page(
                     start_offset, end_offset, page_boundaries
                 )
                 if not chunk_page_info:
-                    logger.debug(f"Chunk {chunk_index}: not found on any page")
+                    logger.debug("Chunk %s: not found on any page", chunk_index)
                     continue
 
                 page_num = chunk_page_info["page_num"]
-                page_boundary = page_boundaries[page_num - 1]
+                page_boundary = next(
+                    (b for b in page_boundaries if b["page"] == page_num), None
+                )
+                if page_boundary is None:
+                    logger.debug(
+                        "Chunk %s: page %s not found in boundaries",
+                        chunk_index,
+                        page_num,
+                    )
+                    continue
                 page_text_length = (
                     page_boundary["end_offset"] - page_boundary["start_offset"]
                 )

nextcloud_mcp_server/vector/processor.py

@@ -582,7 +582,7 @@ async def _index_document(
         assert content_bytes is not None
 
         with trace_operation(
-            "vector_sync.generate_highlights",
+            "vector_sync.compute_chunk_bboxes",
             attributes={
                 "vector_sync.chunk_count": len(chunks),
                 "vector_sync.pdf_size": len(content_bytes),