feat(bf-dcyku): verify cargo-fuzz installation and prerequisites

Add verification note confirming cargo-fuzz 0.13.1 is installed,
fuzz/ directory exists with 7 existing targets, and Rust toolchain
is compatible (nightly 1.98.0). All acceptance criteria PASS.

Closes bf-dcyku.

notes/bf-dcyku.md

@@ -0,0 +1,31 @@
+# bf-dcyku Verification: cargo-fuzz installation and prerequisites
+
+**Date:** 2026-07-06
+
+## Acceptance Criteria Status
+
+✅ **PASS:** `cargo fuzz --version` succeeds and shows version 0.13.1
+
+✅ **PASS:** fuzz/ directory exists with 7 fuzz targets:
+- cmap_parser.rs
+- content.rs
+- lexer.rs
+- object_parser.rs
+- profile_yaml.rs
+- stream_decoder.rs
+- xref.rs
+
+✅ **PASS:** No "cargo-fuzz not found" errors
+
+✅ **PASS:** Rust toolchain compatible (rustc 1.98.0-nightly, cargo 1.98.0-nightly)
+
+## Summary
+
+cargo-fuzz is properly installed and all prerequisites for building fuzz harnesses are met. The workspace has an existing fuzz infrastructure with 7 targets that can serve as references for new harness development.
+
+## Environment
+
+- cargo-fuzz: 0.13.1
+- rustc: 1.98.0-nightly (f20a92ec0 2026-06-07)
+- cargo: 1.98.0-nightly (0b1123a48 2026-06-01)
+- Workspace: /home/coding/pdftract