test(bf-1jx4r): verify profile_yaml fuzz build artifacts

Verification summary:
- profile_yaml binary exists at fuzz/target/x86_64-unknown-linux-gnu/release/profile_yaml
- File size: 58M (non-zero, reasonable)
- Execute permissions: -rwxr-xr-x
- Structure matches other fuzz targets (57-58M range)
- Functional test: libFuzzer initializes successfully

Closes bf-1jx4r.

notes/bf-1jx4r.md

@@ -0,0 +1,53 @@
+# bf-1jx4r: Verify build artifacts and output
+
+## Task
+Verify that the cargo fuzz build produced the expected binary artifacts for the `profile_yaml` fuzz target.
+
+## Verification Results
+
+### Acceptance Criteria Status
+
+✅ **PASS** - profile_yaml binary exists in the fuzz build output directory
+- Location: `/home/coding/pdftract/fuzz/target/x86_64-unknown-linux-gnu/release/profile_yaml`
+
+✅ **PASS** - File has non-zero size
+- Size: 58M (58,541,912 bytes)
+- Comparable to other fuzz targets (57-58M range)
+
+✅ **PASS** - Binary is executable
+- Permissions: `-rwxr-xr-x` (owner: read/write/execute, group/other: read/execute)
+
+✅ **PASS** - Build artifacts match expected structure
+- All fuzz targets follow same pattern:
+  - `content`: 57M
+  - `cmap_parser`: 57M
+  - `lexer`: 57M
+  - `profile_yaml`: 58M
+  - `stream_decoder`: present
+  - `xref`: present
+  - `object_parser`: present
+
+### Functional Test
+
+Tested the binary with correct library path (NixOS requires explicit LD_LIBRARY_PATH):
+```bash
+LD_LIBRARY_PATH=/nix/store/chqq8mpmpyfi9kgsngya71akv5xicn03-gcc-15.2.0-lib/lib \
+  /home/coding/pdftract/fuzz/target/x86_64-unknown-linux-gnu/release/profile_yaml
+```
+
+Result: ✅ libFuzzer initializes successfully, shows expected startup messages:
+- Seed value assigned
+- 1 module loaded with 13,269 inline 8-bit counters
+- 1 PC table loaded with 13,269 PCs
+- Max input length: 4096 bytes (default)
+- Corpus discovery begins
+
+## Summary
+
+The cargo fuzz build for `profile_yaml` completed successfully and produced a fully functional fuzzing binary. The artifact matches the expected structure and size of other fuzz targets in the project.
+
+## Build Context
+
+- Build directory: `/home/coding/pdftract/fuzz/target/x86_64-unknown-linux-gnu/release/`
+- Parent bead: bf-4c49w
+- Built with cargo-fuzz on NixOS system