Add misc unit tests + harden the WAV chunk walk

Fills small coverage gaps:
- shared_memory_test: SharedMemory create-or-open aliasing, move (steal + empty
  the source, no double-free), reset, open-missing.
- wav_test: malformed input -- truncation, bad magic, missing data chunk,
  over-long data size (clamps), odd-sized chunk (word-align skip), and a corrupt
  ~4 GB chunk_size. The reader gains an advance guard so that last case can't wrap
  pos on a 32-bit size_t (x86) or spin the walk; it stops cleanly.
- tool_paths_test: deployed_artifact_path resolution -- next-to-exe, one-dir-up,
  and the not-found fallback -- with real marker files.
- audio_ring_test: an overrun-at-the-seam case (write head near the end: a
  wrapping push that fits vs. an over-capacity wrapping push dropped whole),
  exercising the wrap split + overrun together, not just at offset 0.

The injector bitness check isn't added as a unit test: is_wow64_process is
file-local and the real WOW64 path needs a 32-bit target, so it stays
inspection-covered (and exercised by the x86 injection path).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -115,8 +115,6 @@ as its own commit; "verify" items are confirmed real before any change, and drop
 
 Test coverage:
 - **Dedicated hook tests** — `focus_spoof`, `vk_hook` (present), `d3d9_hook`.
-- **Misc units** — `SharedMemory` RAII/move, `wav` malformed input, `tool_paths` resolution, injector
-  bitness check; strengthen the `audio_ring` overrun-at-seam case.
 
 Features:
 - **Static CRT (`/MT`) for `coop_hook.dll`** (x64 + x86) so it loads in games without the VC++ redist.