release: GGraphDB v1.1.0

[SamuelSupe]

What changed

• Freeze and publish the GGraphDB 1.1 product contract, with GraphQL as the
  public query protocol and the legacy /v1/query/gql text DSL retained for
  1.0 compatibility.
• Add optional PostgreSQL tenant-head CAS coordination for 2-8 writers,
  immutable manifests/write contexts, idempotency ownership, task fencing,
  legacy manifest mirroring, lifecycle operations, and coordinator
  operations/metrics.
• Complete the general property-knowledge-graph surface: entity/relation type
  aliases, labels, relation property schemas, imports, bounded patterns, query
  pagination, reverse indexes, maintenance recovery, SDKs, and bilingual
  documentation.
• Fix CAS write-cache invalidation/write amplification and request-scoped
  index-catalog version reuse that could force large queries onto full scans
  after a head change.
• Mark the authoritative changelog, SDKs, OpenAPI contract, and release
  documentation as v1.1.0 GA.

Compatibility and impact

• Layout version 2 entity, relation, commit, snapshot, and manifest data remains
  readable by GGraphDB 1.0.
• The graphdb binary/module names, GRAPHDB_* settings, X-GraphDB-*
  headers, object keys, and legacy text-DSL route remain compatible.
• PostgreSQL coordination permits 1.0 readers through the monotonic legacy
  manifest mirror and rejects local/1.0 writers to prevent split brain.

Validation

All release evidence is bound to commit
e039c4966318e6e717d7dcf3ce64457dd4bdebc8.

• Clean-snapshot release gate: freeze/naming contract, go test ./...,
  go vet ./..., full go test -race ./..., and real
  release_20260722_01 bidirectional binary compatibility passed.
• Python SDK: 7 passed, 1 skipped.
• OrbStack integration release gate passed: RustFS S3, PostgreSQL CAS,
  writer/reader E2E, load, three cold readers, repair/restore, restart, and
  object-store outage recovery.
• Schema-2 PostgreSQL/RustFS soak passed: 2 writers, 20.00 commits/s for
  30 minutes, 36,000/36,000 commits, 36 compactions, 207 CAS conflicts replayed
  successfully, graph version 36,000, legacy mirror lag 0, outbox backlog 0,
  and a real 1.0 binary reader validation.
• Formal PostgreSQL-to-local rollback passed: outbox backlog 0, mirror lag 0,
  coordination marker removed, PostgreSQL writer fenced, and local writer
  takeover succeeded.