refactor: remove orphaned history_snapshot module

CHANGELOG.md

@@ -9,6 +9,7 @@
 ## [Unreleased]
 
 ### Changed
+- **Removed the orphaned `history_snapshot` module.** `NormalizedSnapshot`/`normalize_history` were documented as a dashboard aggregate but were never exposed by a contract method and were not `#[contracttype]`, so no backend could obtain them. The dashboard surface is now explicitly `get_stats` (cumulative aggregate) alongside `get_severity_telemetry` (per-severity weekly windows); the module, its `lib.rs` registration, and its ownership list entries were removed (#467)
 - **Fuzz targets now assert the contract's documented semantics, not just panic-freedom.** `compute_result` and `validate_config` previously ran the function and let libFuzzer watch for a crash; on code guarded throughout by `checked_mul`/`checked_neg` that finds essentially nothing, and a semantic regression (e.g. treating `mttr == threshold` as a violation) would have left the nightly job green. Both targets now compare every input against `apexchainx_calculator::spec` and fail on any disagreement. Each target header states what it asserts and what it does not; `docs/FUZZING_GUARANTEES.md` states the suite-wide guarantees and the policy for resolving an implementation-vs-documentation conflict
 - **`ts/historyPagination.ts` capped pages at 50 where the contract caps at 200** (`history::MAX_PAGE_SIZE`, #409), so a backend paging with `limit = 200` received 50 entries and — because the mirror also derived `hasMore` from the returned length — could conclude history had ended. It also coerced `limit = 0` up to 1, returning an entry where the contract returns an empty page, and reported `hasMore: false` where the contract reports `true`. The helper now imports the contract-generated `MAX_PAGE_SIZE` and mirrors `end = min(offset + limit, total)` / `hasMore = end < total` exactly
 - **`ts/configVersionHash.ts` computed an unrelated hash.** It ran djb2 over a canonical JSON serialisation of a snapshot whose fields (`penaltyBps`, `rewardBps`) do not exist on the contract, so a backend comparing it against `get_config_version_hash` would have seen a mismatch on every call. It now reproduces the contract's polynomial rolling hash exactly, in `BigInt` `u64` arithmetic, and is asserted equal to a contract-recorded value

apexchainx_calculator/src/lib.rs

@@ -49,7 +49,6 @@ mod event_schema;
 pub mod fuzz_spec;
 pub mod governance;
 pub mod history;
-pub mod history_snapshot;
 pub mod metadata;
 pub mod metrics;
 /// Parity checker: compares current `compute_result` against the locked-in
@@ -2099,6 +2098,12 @@ impl SLACalculatorContract {
     // -------------------------------------------------------------------
 
     /// Returns the cumulative SLA performance statistics.
+    ///
+    /// This is the contract's dashboard aggregate: together with
+    /// `get_severity_telemetry` (per-severity weekly windows) it is the
+    /// supported surface for dashboard telemetry. Cumulative totals here
+    /// subsume the windowed view; consumers that need a windowed summary
+    /// should read `get_severity_telemetry` rather than re-scan history.
     pub fn get_stats(env: Env) -> Result<SLAStats, SLAError> {
         Self::check_version(&env)?;
         env.storage()

docs/MODULE_OWNERSHIP.md

@@ -29,7 +29,7 @@ reviewers and merge bottlenecks are reduced.
 | **Contract Core** | Contract Core reviewers | `apexchainx_calculator/src/lib.rs`, `calculation.rs`, `config.rs`, core types and entrypoints |
 | **Contract Governance** | Contract Core reviewers | `governance.rs`, `config_freeze.rs`, role management, pause/unpause |
 | **Contract Infrastructure** | Contract Core reviewers | `storage_version.rs`, `version_negotiation.rs`, `deployment_policy.rs`, `cross_contract_safety.rs` |
-| **Contract Data Layer** | Contract Core reviewers | `history.rs`, `history_snapshot.rs`, `config_metadata.rs`, `config_bundle.rs`, `metadata.rs` |
+| **Contract Data Layer** | Contract Core reviewers | `history.rs`, `config_metadata.rs`, `config_bundle.rs`, `metadata.rs` |
 | **Event System** | Contract Core reviewers | `event.rs`, `event_schema.rs`, `event_correlation.rs`, event test modules |
 | **Audit & Telemetry** | Contract Core reviewers | `audit_state.rs`, `error_responses.rs` |
 | **Testing** | Contract Core reviewers | `tests.rs`, `fuzz_tests.rs`, fuzz targets, property tests |
@@ -62,7 +62,6 @@ All paths are relative to `apexchainx_calculator/src/`.
 | `config_freeze.rs` | Contract Governance | `freeze_config`, `unfreeze_config`, `is_config_frozen` | **Medium** |
 | `metadata.rs` | Contract Governance | `pause`, `unpause`, `is_paused`, `get_pause_info`, `require_not_paused` | **High** |
 | `history.rs` | Contract Data Layer | `get_history`, `prune_history`, `prune_history_by_age`, `get_history_page`, `get_history_page_with_meta`, `get_history_by_outage`, `get_latest_by_outage`, `get_config_count`, `set_retention_limit`, `get_retention_limit` | **High** |
-| `history_snapshot.rs` | Contract Data Layer | `normalize_history` | **Medium** |
 | `config_metadata.rs` | Contract Data Layer | `record_config_update`, `get_last_config_update` | **Medium** |
 | `config_bundle.rs` | Contract Data Layer | (composed types for `get_config_bundle`) | **Low** |
 | `audit_state.rs` | Audit & Telemetry | (composed types for `get_full_audit_state`) | **Low** |
@@ -257,7 +256,7 @@ All paths relative to `.github/workflows/`.
 | `calculation.rs`, `config.rs` | 1 reviewer from Contract Core |
 | `governance.rs`, `config_freeze.rs` | 1 reviewer from Contract Governance |
 | `storage_version.rs`, `version_negotiation.rs`, `cross_contract_safety.rs` | 1 reviewer from Contract Infrastructure |
-| `history.rs`, `history_snapshot.rs`, `config_metadata.rs` | 1 reviewer from Contract Data Layer |
+| `history.rs`, `config_metadata.rs` | 1 reviewer from Contract Data Layer |
 | `event.rs`, `event_schema.rs`, `event_correlation.rs` | 1 reviewer from Event System |
 | Any `.github/workflows/*.yml` | 1 reviewer from DevOps |
 | Any `docs/*.md` | 1 reviewer from Docs |