v3.0.0

Breaking

• JSONL version is 2. Rebuild kinds own_pcm_* / pcm_stale / dependency_pcm_stale are now own_bmi_* / bmi_stale / dependency_bmi_stale. Field pcm_path is bmi_path.
• Object-cache profile cb-object-cache-v4. Keys: toolchain_root, compiler, compiler_signature, compiler_version, std_module (replacing llvm / cxx / cxx_sig / clang_ver / std_cppm). Old caches invalidate once on profile mismatch.
• cb test --help prints CB usage and exits; it no longer forwards to test_runner.

Changed

• JUnit XML is CI-readable for GitHub Actions test-summary: classname is path:line, name is the case title (no test_case -> / scenario -> noise), failed cases point at the assertion call site, nested BDD steps fold under the parent scenario with a step list in <system-out>, and suite failures/errors count cases.
• Project BMI filenames keep dots (only : → -) for Clang -fprebuilt-module-path lookup.
• Two-phase modular rebuilds enqueue pcm→.o as a separate ready job after BMI publish.
• Faster CB warm rediscovery (closer to Ninja no-op).
• Internal CB structure (Clang driver, cache stores, table-driven CLI, cache_admin) with no new public flags or events beyond the above.

Toolchain

• Minimum: Clang 21 with libc++ modules (unchanged).

JSONL

• Envelope version: 2 (was 1).
• Schema: docs/jsonl-schema.json.

See CHANGELOG.md for the full entry.