Add 02335 T0 analyst report

Request:
- Generate an analyst report for HK IPO ticker 02335.

Changes:
- Archived the official HKEXnews 02335 prospectus PDF and extracted text under project-relative data paths.
- Seeded 02335 T0 prospectus facts, source references, sync state, and analysis snapshots.
- Generated reports/2026-06-15_02335_T0_prospectus_analysis.md in Simplified Chinese with concrete T0/T1/T2/D1 dates and short-exit T2/D1 discipline.
- Made PDF text extraction tolerant of invalid Unicode surrogate characters emitted by pypdf.

Verification:
- Compiled archive_hkex_documents.py, generate_ipo_report.py, build_analysis_dataset.py, extract_pdf_text.py, and update_sync_state.py.
- Ran SQLite integrity_check and foreign_key_check.
- Verified the archived 02335 PDF hash, extracted-text manifest row, and analysis dataset row.
- Ran git diff --check.

Next useful context:
- 02335 is currently T0_prospectus; T1_allotment is pending for 2026-06-23.

scripts/extract_pdf_text.py

@@ -89,6 +89,10 @@ def import_pypdf():
     return PdfReader
 
 
+def utf8_safe_text(value: str) -> str:
+    return value.encode("utf-8", "replace").decode("utf-8")
+
+
 def extract_text(pdf_path: Path) -> tuple[str, int, int]:
     PdfReader = import_pypdf()
     reader = PdfReader(str(pdf_path))
@@ -98,7 +102,7 @@ def extract_text(pdf_path: Path) -> tuple[str, int, int]:
         text = page.extract_text() or ""
         if text.strip():
             pages_with_text += 1
-        cleaned_text = "\n".join(line.rstrip() for line in text.strip().splitlines())
+        cleaned_text = utf8_safe_text("\n".join(line.rstrip() for line in text.strip().splitlines()))
         chunks.append(f"\n\n--- page {index} ---\n{cleaned_text}\n")
     return "".join(chunks).strip() + "\n", len(reader.pages), pages_with_text