feat: build, chain-validate, and seed evo snapshot state - #7593

… sign change

The mask for rejecting out-of-range trailing bits promotes through operator~ to a negative int before its implicit conversion back to uint8_t, which clang's implicit-integer-sign-change check reports for every bitset whose size is not a multiple of eight. The evo snapshot unit tests are the first to deserialize such bitsets under the sanitizer job. Same bits, stated explicitly.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The codec PR shipped UnserializeBounded without its unit coverage; add the malformed/canonical decode matrix and the round-trip checks from the original series.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The signal map normalizes iteration order, so wire order was unobservable after decode: any permutation of the same signal set was accepted by Unserialize() and reserialized sorted, violating the require_canonical_order contract that every other top-level collection enforces. Require the strictly ascending bit order the serializer emits at the only point where wire order is visible, which also subsumes the duplicate-bit rejection.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…LMQ size

-llmqtestparams and -llmqdevnetparams mutate size, minSize, threshold, and dkgBadVotesThreshold on the CChainParams copy of the LLMQ table, so a commitment produced under a supported non-default quorum size was rejected by the static Consensus::available_llmqs sizing: a larger size exceeded the read bound and a smaller one failed the exact comparison. The context-free layer now enforces an allocation ceiling (EVO_SNAPSHOT_MAX_QUORUM_SIZE) plus signers/validMembers internal consistency; exact sizing already happens in the chain-aware validation, which iterates the effective consensus.llmqs table and calls VerifySizes against it. Count, rotation, and interval fields stay on the static table since the overrides cannot change them.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Validate() bounded only the MNHF map's cardinality: out-of-money-range credit pool amounts, a currentLimit above locked, signal bits at or above VERSIONBITS_NUM_BITS, and signal heights outside [0, base height] all received a canonical snapshot hash. ConstructCreditPool guarantees 0 <= currentLimit <= locked in every deployment branch and consensus admits MNHF signals only for bits below VERSIONBITS_NUM_BITS at their mined height, so enforce exactly those invariants.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CDeterministicMNList's HAMT hashes proTxHash by its first 8 bytes, so a snapshot supplying up to 100,000 distinct, canonically ordered hashes sharing one 64-bit prefix made every AddMN copy the whole immer collision node: quadratic work and allocation from a single crafted snapshot. Real proTxHashes are uniform txids, where even one shared prefix among 100,000 has probability ~3e-10, so bound collision runs at 8. Enforced on the sorted base list during decoding (before the inserts), on the merged current-plus-additions prefix set before every historical diff application, and as an object-level invariant; the run detector sorts a plain vector so it cannot itself be driven into hash-collision buckets.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The top-level decoder always constructs a fresh local, but direct stream >> data into a reused CQuorumSnapshotData retained prior commitments and rotation entries and could exceed the incoming count bounds. Clear the three vectors up front, matching CEvoSnapshot::Unserialize.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The per-diff operation budget charges only additions, updates, and removals, so a few hundred bytes of zero-operation diff entries could drag a maximum-size list across the whole table-wide history horizon: every entry traverses, sorts, and canonically hashes the full reconstructed list (~19M record serializations from a small input). Charge a cumulative record budget up front in ReconstructHistoricalMNLists. The table-wide horizon sums types no single network enables together, so even a ceiling-sized list under a fully loaded real configuration stays well below half the budget.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Second code PR of the assumeutxo M4 series: BuildEvoSnapshot() collects commitments, rotation snapshots, historical MN-list diffs, and exact score modifiers from chain state; ValidateEvoSnapshotAgainstChain() verifies a decoded snapshot against the block index, deployments, and quorum reconstruction; and the EvoDB seeding surface writes exactly the state reconstruction later reads. The chain-aware implementations live in the header-less evo/snapshot_chain.cpp unit so the codec in evo/snapshot.cpp never includes validation.h (no evo/snapshot -> validation cycle); ChainstateManager code is untouched here and stays in validation.cpp later in the series.

Parameter-derived quorum counts are carried as maxima rather than exact requirements: a young chain, a freshly activated type, or a rotation type whose horizon predates activation legitimately has less history, and requiring the full horizon made dumptxoutset fail on valid chain state (flagged as blocking by review on the original M4 PR). Completeness is anchored by the completion-time CbTx quorum merkle root, the historical-diff and modifier tallies, and completion-time quorum reconstruction; two regression tests fail against exact-count enforcement. GetHashModifier() prefers a seeded exact modifier when work-block data is unavailable and cross-checks it when present; the mismatch error stays unreachable until the load integration seeds modifiers. GetDeterministicMNListHash() switches to the canonical codec hash (dev-channel-only marker-compat caveat in the PR description).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>