dash: T1c byte-parity KAT vs live p2pool-dash oracle corpus (share-v16)

Close the T1c serialization-parity gap the 2026-07-21 join-lane audit
flagged: test_dash_conformance.cpp only exercised synthetic/out-of-band
vectors, with no byte-parity test against a real p2pool-dash node.

Adds:
  - test/data/dash_oracle_corpus.hpp: 29 distinct canonical shares captured
    off a controlled p2pool-dash node JOINED to the live public sharechain
    (share-v16 / min-proto-1700), each raw wire-entry cross-validated
    byte-identical across 4 independent peers, deduped by share_hash.
  - test/test_dash_oracle_byte_parity.cpp: round-trips every canonical
    SHARE_RAW through the production load_share -> DashFormatter::Read ->
    DashFormatter::Write path and asserts serialize(parse(raw)) == raw
    (the exact condition for a relayed share to VERIFY_PASS on the fork),
    plus semantic cross-checks (prev_hash / donation / new_tx_count /
    pubkey_hash -> payout_script) against the fork's SHARE_RECV fields.

Result: 30/30 pass. c2pool's DASH v16 layout already byte-matches the
canonical fork; no serialization divergence found. Promotes the real
captured-corpus KAT the conformance suite was missing.

Author: frstrtr

test/CMakeLists.txt

@@ -263,6 +263,21 @@ if (BUILD_TESTING AND GTest_FOUND)
     target_link_libraries(test_dash_conformance PRIVATE c2pool_payout c2pool_hashrate c2pool_merged_mining)  # OBJECT-lib SCC direct-naming (#22/#39): core stratum/web_server TUs
     gtest_add_tests(test_dash_conformance "" AUTO)
 
+    # DASH share-v16 BYTE-PARITY KAT (T1c gate): round-trips REAL captured
+    # p2pool-dash oracle-gate wire bytes (test/data/dash_oracle_corpus.hpp)
+    # through the production load_share/DashFormatter path and demands byte
+    # identity — the real-corpus test the 2026-07-21 audit flagged as missing.
+    # Mirrors the test_dash_conformance link set.
+    add_executable(test_dash_oracle_byte_parity test_dash_oracle_byte_parity.cpp)
+    target_link_libraries(test_dash_oracle_byte_parity PRIVATE
+        GTest::gtest_main GTest::gtest
+        dash_x11 core
+        nlohmann_json::nlohmann_json
+        ${Boost_LIBRARIES}
+    )
+    target_link_libraries(test_dash_oracle_byte_parity PRIVATE c2pool_payout c2pool_hashrate c2pool_merged_mining)  # OBJECT-lib SCC direct-naming (#22/#39): core stratum/web_server TUs
+    gtest_add_tests(test_dash_oracle_byte_parity "" AUTO)
+
     # DASH min-protocol-version ratchet gate KAT (#643, option a): pure, header-only
     # policy object; no socket/ltc/pool dependency. Mirrors the test_dash_conformance link set.
     add_executable(test_dash_min_protocol_gate test_dash_min_protocol_gate.cpp)