fix: use lopdf fork with zlib checksum fallback for encrypted PDFs

Points to firecrawl/lopdf branch that falls back to raw deflate when
zlib adler32 checksum is corrupted after RC4 decryption. Fixes 5
encrypted BrokerCheck PDFs that were misclassified as scanned.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Cargo.toml

@@ -10,7 +10,7 @@ repository = "https://github.com/firecrawl/pdf-inspector"
 
 [dependencies]
 # PDF parsing
-lopdf = { git = "https://github.com/J-F-Liu/lopdf", features = ["rayon"] }
+lopdf = { git = "https://github.com/firecrawl/lopdf", branch = "firecrawl/zlib-checksum-encrypted", features = ["rayon"] }
 
 # Error handling
 thiserror = "2.0"