[codex] Guard PDB field-list recursion

[plafosse]

Warning

This patch was completely vibe coded. Treat it as a CI and validation candidate, not a reviewed final fix.

Refs Vector35/binaryninja#1620

Rationale

The D2 Sentry crash points at a stack overflow while Binary Ninja imports PDB type information. The likely failure path is below pdb-ng's existing type-resolution guard: pdb-rs recursively parses nested LF_FIELDLIST records while building raw TypeData, so malformed or adversarial PDB input can recurse before pdb-ng gets a chance to apply its own type_stack limits.

This PR changes that parser path to fail closed with a typed recursion-limit error instead of exhausting the process stack.

What Changed

• Vendor the pinned pdb-rs source used by pdb-ng so the parser fix is local to the plugin build.
• Switch both pdb-ng manifests to use the vendored path dependency.
• Add TypeRecordRecursionLimit and cap nested LF_FIELDLIST parsing at 32 levels.
• Add a focused unit test for the nested field-list case.
• Include vendored source files in the CMake dependency list so changes trigger rebuilds.

Validation

• Passed: cargo +1.91.1-aarch64-apple-darwin test --manifest-path /private/tmp/pdb-rs-test/Cargo.toml --offline --lib fieldlist_recursion_limit
• Note: direct workspace Cargo runs are blocked locally by unrelated parent-workspace/toolchain issues, so CI should validate the integrated build on this test_ branch.