ABI: generate and own deterministic cached bytecode artifacts

Parent: #140 Profiles: #163, #164 Roadmap: #134

Implement the three shared Home/Bun CachedBytecode.zig imports as one exact ownership boundary:

• generateCachedModuleByteCodeFromSourceCode
• generateCachedCommonJSProgramByteCodeFromSourceCode
• CachedBytecode__deref

Acceptance:

• Implement the exact pinned signatures and explicit opaque-handle ownership.
• Define a versioned, endian-stable artifact with source kind, URL, source payload, lengths, and integrity digest.
• Validate ESM/CommonJS syntax through the production parser before publishing bytes.
• Keep all out-parameters cleared on failure and tolerate null/empty URL strings according to the pinned BunString ABI.
• Add allocation-failure, invalid-source, determinism, kind-separation, lifetime, and concurrent-generation tests.
• Add compiled Home/Bun consumer evidence in Debug and ReleaseSafe.
• Refresh both exact inventories, #140/#163/#164, and concise ABI documentation.

Completion evidence:

• Implementation, exact consumers, inventories, CI, and docs: 4c1b2873
• Allocation rollback and concurrency/TSan hardening: 367a3df5
• Focused unit slice: 6/6, zero failures/leaks
• Concurrent-generation TSan slice: 3/3, zero failures/leaks/races
• Home compiled consumer: 388/388 symbols in Debug and ReleaseSafe
• Dedicated Bun compiled consumer: Debug and ReleaseSafe
• Current inventories: Home 404/471 (67 pending), Bun 396/461 (65 pending), zero unclassified

Completed on main. The pinned allocator-vtable lifetime now owns a deterministic, syntax-validated ZJSCBC01 artifact without misrepresenting it as JavaScriptCore private serialization; failure paths are atomic and concurrent generation is TSan-clean.