Ports lumbda.py _emit_circuit_to_ops_bin_stream to C tier. Walks a
Scheme registers + ops list, writes each 56-byte QECCOPS1 op record
straight to disk via fopen/fwrite, then seeks back to patch the n_ops
header at the tail. O(1) host memory regardless of n_ops.
Cross-tier byte-identity verified:
* 500-op mixed-tag synthetic circuit on host: Python ↔ C identical
* real-point-add n+1=5 (p=11, 94,214 ops, 5.0 MB) inside VM
* real-point-add n+1=9 (p=251, 674,872 ops, 36 MB) inside VM
sha256 matches every width.
Speedup on equal Scheme source (build + emit combined):
* n+1=5: Python 56.8 s → C 1.1 s (52×)
* n+1=9: Python 365 s → C 8.4 s (43×)
Combined ratio exceeds the prior 11-16× C-tier envelope because the
build phase (Phase B mod-arith construction) also accelerates on C;
emit-only ratio is ~3-9× and grows with op count.
C test suite: 85 → 88 passing (emit-stream-basic, alloc-free, empty).
Shared functional suite: 205/205 still passing on both tiers.
Implementation notes:
* pack_op_record packs u32 kind + u32 pad + 6× u64 LE, matching
op-specs->bytes byte layout exactly.
* Layout hashtable Symbol → fixnum base, mirroring walk-circuit-ops.
* NO_SLOT sentinel: 0xFFFFFFFFFFFFFFFF written directly to u64 slots
that the Scheme side did not populate.
* libc's default fwrite buffer (~4 KB) handles batching at ~73 ops
per write — same throughput class as Python tier's 8 KiB list batch.