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>

common/include/coop/wav.hpp

@@ -132,7 +132,15 @@ inline bool wav_read(const std::wstring& path, WavData& out)
 			out.pcm.assign(all.begin() + body, all.begin() + body + n);
 			have_data = true;
 		}
-		pos = body + chunk_size + (chunk_size & 1); // chunks are word-aligned
+		// Advance to the next chunk (word-aligned). Guard a corrupt over-long chunk_size: it would
+		// wrap `pos` on a 32-bit size_t (x86) and spin the loop on garbage, and there's nothing valid
+		// past a chunk that claims more than the file holds anyway.
+		const std::size_t advance = static_cast<std::size_t>(chunk_size) + (chunk_size & 1);
+		if (advance > all.size() - body)
+		{
+			break;
+		}
+		pos = body + advance;
 	}
 	return have_fmt && have_data;
 }