chore(openspec): archive phase-5-scale-ecosystem — 68/68 tasks complete

WS1 (Rust SDK), WS2 (A2A Authorization), WS5 (Developer Experience)
all delivered, QA gates passed, committed to main.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

openspec/changes/phase-5-scale-ecosystem/.openspec.yaml

@@ -1,58 +0,0 @@
-schema: spec-driven
-id: phase-5-scale-ecosystem
-title: "Phase 5 — Scale & Ecosystem"
-status: proposed
-created: "2026-04-02"
-author: Virtual Architect
-phase: 5
-theme: "Scale & Ecosystem — making SentryAgent.ai the definitive standard for agent identity globally"
-
-workstreams:
-  - id: ws1
-    name: Rust SDK
-    directory: specs/rust-sdk
-  - id: ws2
-    name: Agent-to-Agent (A2A) Authorization
-    directory: specs/a2a-authorization
-  - id: ws3
-    name: Advanced Analytics Dashboard
-    directory: specs/analytics-dashboard
-  - id: ws4
-    name: Public API Gateway & Rate Limiting SaaS
-    directory: specs/api-gateway-tiers
-  - id: ws5
-    name: Developer Experience (DX) Improvements
-    directory: specs/developer-experience
-  - id: ws6
-    name: AGNTCY Compliance Certification Package
-    directory: specs/agntcy-compliance
-
-artifacts:
-  - proposal.md
-  - design.md
-  - specs/rust-sdk/spec.md
-  - specs/a2a-authorization/spec.md
-  - specs/analytics-dashboard/spec.md
-  - specs/api-gateway-tiers/spec.md
-  - specs/developer-experience/spec.md
-  - specs/agntcy-compliance/spec.md
-  - tasks.md
-
-dependencies:
-  new:
-    - tokio
-    - reqwest
-    - serde
-    - serde_json
-    - swagger-ui-dist
-    - elements-api
-    - archiver
-    - recharts
-    - date-fns
-  existing:
-    - express
-    - postgresql
-    - redis
-    - stripe
-    - next
-    - commander