feat: add Temporal workflow orchestration to backend-development plugin (#125)

* docs: enhance payment-integration agent with critical security guidance

Add evidence-based security requirements from Stripe, PayPal, OWASP:
- Webhook security (signature verification, idempotency, quick response, server validation)
- PCI compliance essentials (tokenization, server-side validation, environment separation)
- Real-world failure examples (processor collapse, Lambda failures, malicious price manipulation)

Minimal expansion: 32 to 57 lines (25 lines added)

* feat: add Temporal workflow orchestration to backend-development plugin

Add comprehensive Temporal workflow orchestration support with 1 agent and 2 skills:

**Agent:**
- temporal-python-pro: Python SDK expert for durable workflows, saga patterns,
  async/await patterns, error handling, and production deployment

**Skills:**
- workflow-orchestration-patterns: Language-agnostic patterns for workflows vs
  activities, saga compensation, entity workflows, and determinism constraints
- temporal-python-testing: Progressive disclosure testing guide with unit testing,
  integration testing, replay testing, and local development setup

**Changes:**
- Add agent: plugins/backend-development/agents/temporal-python-pro.md (311 lines)
- Add skill: plugins/backend-development/skills/workflow-orchestration-patterns/ (286 lines)
- Add skill: plugins/backend-development/skills/temporal-python-testing/ (SKILL.md + 4 resource files)
- Update marketplace.json: backend-development plugin v1.2.2 → v1.2.3
- Update docs/agents.md: 85 → 86 agents
- Update docs/agent-skills.md: 55 → 57 skills

**Content Sources:**
- Official Temporal documentation (docs.temporal.io)
- Temporal Python SDK guide (python.temporal.io)
- Temporal architecture docs (github.com/temporalio/temporal)
- OWASP best practices for distributed systems

Addresses #124

---------

Co-authored-by: Kiran Eshwarappa <kiran.eshwarapa@gmail.com>

.claude-plugin/marketplace.json

@@ -101,8 +101,8 @@
     {
       "name": "backend-development",
       "source": "./plugins/backend-development",
-      "description": "Backend API design, GraphQL architecture, and test-driven backend development",
-      "version": "1.2.2",
+      "description": "Backend API design, GraphQL architecture, workflow orchestration with Temporal, and test-driven backend development",
+      "version": "1.2.3",
       "author": {
         "name": "Seth Hobson",
         "url": "https://github.com/wshobson"
@@ -115,7 +115,10 @@
         "api-design",
         "graphql",
         "tdd",
-        "architecture"
+        "architecture",
+        "temporal",
+        "workflow-orchestration",
+        "distributed-systems"
       ],
       "category": "development",
       "strict": false,
@@ -125,12 +128,15 @@
       "agents": [
         "./agents/backend-architect.md",
         "./agents/graphql-architect.md",
-        "./agents/tdd-orchestrator.md"
+        "./agents/tdd-orchestrator.md",
+        "./agents/temporal-python-pro.md"
       ],
       "skills": [
         "./skills/api-design-principles",
         "./skills/architecture-patterns",
-        "./skills/microservices-patterns"
+        "./skills/microservices-patterns",
+        "./skills/workflow-orchestration-patterns",
+        "./skills/temporal-python-testing"
       ]
     },
     {