docs: update CHANGELOG.md with all unreleased features (#60)

Co-authored-by: Bot <bot@example.com>

Author: ayomideadeniran

CHANGELOG.md

@@ -13,8 +13,36 @@
 - `get_result_schema` — explicit schema descriptor for SLA result encoding (status, payment type, rating symbols)
 - `calculate_sla_view` — read-only simulation of SLA calculation without state mutation or auth requirement
 - `get_config_snapshot` — ordered snapshot of all severity configs with version tag
+- `migrate` — admin-only migration function to bump the storage schema version (SC-021)
+- `get_admin` — read the current admin address
+- Two-step admin transfer governance functions: `propose_admin`, `accept_admin`, `cancel_admin_proposal`, and `get_pending_admin` (SC-024, SC-063)
+- Two-step operator handoff governance functions: `propose_operator`, `accept_operator`, `cancel_operator_proposal`, and `get_pending_operator` (SC-024, SC-064)
+- `renounce_admin` — admin-only irreversible governance renouncement (SC-065)
+- `is_paused` — query if the contract is paused
+- `get_pause_info` — query pause reason, timestamp, and initiator metadata
+- `list_configs` — read all severity configurations as a Map
+- `get_last_config_update` — cheap invalidation check returning metadata (ledger sequence) on the most recent configuration update (#4)
+- `get_failure_schema` — returns the full catalogue of typed failure codes mapping numeric error codes to machine-readable labels and descriptions (SC-W5-046)
+- `get_config_bundle` — combines configuration snapshot and result schema in a single read for one-shot backend bootstrapping (#1)
+- `get_contract_metadata` — returns static contract capabilities including features, supported severities, storage/result schema versions (SC-060)
+- `prune_history_by_age` — admin-only history compaction removing entries older than a specified duration (SC-063)
+- Paginated history access: `get_history_page` returning bounded history page (SC-059)
+- `get_history_by_outage` — query all history entries matching a given outage identifier (SC-060)
+- `get_latest_by_outage` — query the most recent history entry for a given outage identifier (SC-061)
+- `get_config_count` — read total number of configured severity tiers (SC-079)
+- `get_storage_version` — query the current storage version stamped in storage
+- Configurable retention limit functions: `set_retention_limit` and `get_retention_limit` (SC-013)
+- `get_migration_state` — query storage version and migration posture (SC-021)
+- `get_version_info` — version negotiation snapshot for backend startup handshake (SC-W5-029)
+- Event Correlation IDs — cross-contract tracing via deterministic correlation IDs generated by `generate_correlation_id` from ledger sequence and formatted with `correlation_event_topics` (SC-W5-079)
+- Settlement Intent Event (`set_int`) — Published on every `calculate_sla` call alongside `sla_calc` event for backend reconciliation. It uses topics `(set_int, v1, severity)` and payload `(outage_id: Symbol, status: Symbol, payment_type: Symbol, amount: i128, config_version_hash: u64, recorded_at: u64)` (SC-W5-041)
 
 ### Changed
+- `pause` now requires a `reason: String` parameter, records pause metadata (reason, timestamp, initiator), and emits an event payload with the paused status (breaking)
+- `calculate_sla` now:
+  - Emits a settlement intent event (`set_int`) alongside the SLA calculation event
+  - Enforces a configurable retention limit (SC-013) and drops the oldest entry when the limit is exceeded (SC-062)
+  - Performs configuration parameter validation (SC-W5-046)
 - `get_stats` now returns a `SLAStats` struct; callers should use field access rather than tuple destructuring
 - History entries returned by `get_history` include `schema_version` for result envelope versioning