7473bb7e44
Address the Codex GPT-5.5 review of the standalone fake C++ gRPC Shard worker. Four root protocol defects fixed: - Fail closed before SessionOpen: a per-session `opened` flag gates chunk/decode so no activation bypasses lifecycle, cancellation, epoch or flow-control state (terminal ERROR_CODE_INTERNAL), even when an out-of-band Cancel created placeholder state. - Strict flow-control negotiation: NegotiateFlow takes the strictest of peer-vs-worker bounds (mirrors codec.negotiate_flow_control) and the negotiated per-session max_chunk_bytes is enforced on every bundle instead of trusting the peer proposal. - In-stream ReleaseSignal now erases session state immediately. - SessionOpen rejects incompatible schema, fingerprint, and shard-range identity and reports the worker's own served fingerprint rather than echoing the caller. Adds 9 regression tests (worker suite 18 -> 27). Real gates on the rebuilt pinned-gRPC binary: cmake build exit 0; ctest 2/2; worker pytest 27 passed; harness+protocol 63 passed; compileall 0; diff --check clean; ldd/nm show 0 llama/ggml linkage. DGR-033 passes -> true. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>