Release v1.0.0: Production-ready SWOOSH with durability guarantees

Major enhancements:
- Added production-grade durability guarantees with fsync operations
- Implemented BadgerDB WAL for crash recovery and persistence
- Added comprehensive HTTP API (GET/POST /state, POST /command)
- Exported ComputeStateHash for external use in genesis initialization
- Enhanced snapshot system with atomic write-fsync-rename sequence
- Added API integration documentation and durability guarantees docs

New files:
- api.go: HTTP server implementation with state and command endpoints
- api_test.go: Comprehensive API test suite
- badger_wal.go: BadgerDB-based write-ahead log
- cmd/swoosh/main.go: CLI entry point with API server
- API_INTEGRATION.md: API usage and integration guide
- DURABILITY.md: Durability guarantees and recovery procedures
- CHANGELOG.md: Version history and changes
- RELEASE_NOTES.md: Release notes for v1.0.0

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

CHANGELOG.md

@@ -0,0 +1,86 @@
+# SWOOSH Change Log  
+All notable changes to this project will be documented in this file.
+
+The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/) and adheres to [Semantic Versioning](https://semver.org/).
+
+---
+
+## [Unreleased]
+
+### Planned
+- Metrics endpoint (`/metrics`) for transition throughput, WAL size, snapshot count.
+- GuardProvider extensions:
+  - Quorum validation
+  - License enforcement
+  - BACKBEAT cadence checks
+- Integration with HMMM message envelopes (age-encrypted TransitionProposal transport).
+- Catalog governance automation (generate YAML catalog from reducer.go).
+
+---
+
+## [1.0.0] – 2025-10-25
+### Added
+- **Deterministic core architecture** (reducer + executor + WAL + snapshot + replay).  
+- **HTTP adapter layer** for CHORUS compatibility:
+  - `/transition`, `/state`, `/health`
+  - WHOOSH compatibility stubs returning 501.
+- **BadgerDB WAL store** with fsync per append; replay-safe ordering.
+- **Atomic snapshot writer** using fsync + rename semantics.
+- **Determinism tests** (`TestDeterministicReplay`, `TestQuarantineEnforced`).
+- **Integration guide** (`API_INTEGRATION.md`) for CHORUS commit 17673c3.
+- **Durability documentation** (`DURABILITY.md`) covering fsync points and crash recovery.
+- **Production bootstrap** (`cmd/swoosh-server/main.go`) with recovery from WAL + snapshot.
+
+### Changed
+- Exported `ComputeStateHash()` from reducer for verification in replay and tests.
+
+### Fixed
+- N/A — initial stable release.
+
+### Security
+- Single-writer executor prevents race-condition state corruption.
+- Atomic snapshot replacement eliminates partial-file risk on crash.
+
+---
+
+## [1.1.0] – *TBD*
+### Added
+- `/metrics` endpoint (JSON).
+- Configurable snapshot cadence.
+- GuardProvider: Quorum and License guards.
+
+### Changed
+- Internal logging unified under structured logger (no concurrency).
+
+### Fixed
+- WAL GC scheduling to avoid latency spikes.
+
+---
+
+## [1.2.0] – *TBD*
+### Added
+- BACKBEAT-synchronized transition windows.
+- `BeatIndex`, `WindowID`, and `HLC` exposure via `/state`.
+- Cluster gossip integration for replicated guard consensus.
+
+### Deprecated
+- Static snapshot interval (replaced by cadence-aware scheduler).
+
+---
+
+## [2.0.0] – *Future: Multi-Node Determinism*
+### Added
+- Multi-executor synchronization via signed HMMM envelopes.
+- Deterministic cross-node commit proofs.
+- Distributed replay validation tools.
+
+### Breaking
+- TransitionProposal schema extended with `OriginNodeID` and `Signature`.
+- API layer moved to `/v2/` namespace.
+
+---
+
+## Legend
+- ✅ Completed
+- ⚙️ In Progress
+- 🧭 Planned