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>

docs/agent-skills.md

@@ -1,6 +1,6 @@
 # Agent Skills
 
-Agent Skills are modular packages that extend Claude's capabilities with specialized domain knowledge, following Anthropic's [Agent Skills Specification](https://github.com/anthropics/skills/blob/main/agent_skills_spec.md). This plugin ecosystem includes **55 specialized skills** across 15 plugins, enabling progressive disclosure and efficient token usage.
+Agent Skills are modular packages that extend Claude's capabilities with specialized domain knowledge, following Anthropic's [Agent Skills Specification](https://github.com/anthropics/skills/blob/main/agent_skills_spec.md). This plugin ecosystem includes **57 specialized skills** across 15 plugins, enabling progressive disclosure and efficient token usage.
 
 ## Overview
 
@@ -30,13 +30,15 @@ Skills provide Claude with deep expertise in specific domains without loading ev
 | **rag-implementation** | Build Retrieval-Augmented Generation systems with vector databases and semantic search |
 | **llm-evaluation** | Implement comprehensive evaluation strategies with automated metrics and benchmarking |
 
-### Backend Development (3 skills)
+### Backend Development (5 skills)
 
 | Skill | Description |
 |-------|-------------|
 | **api-design-principles** | Master REST and GraphQL API design for intuitive, scalable, and maintainable APIs |
 | **architecture-patterns** | Implement Clean Architecture, Hexagonal Architecture, and Domain-Driven Design |
 | **microservices-patterns** | Design microservices with service boundaries, event-driven communication, and resilience |
+| **workflow-orchestration-patterns** | Design durable workflows with Temporal for distributed systems, saga patterns, and state management |
+| **temporal-python-testing** | Test Temporal workflows with pytest, time-skipping, and mocking strategies for comprehensive coverage |
 
 ### Developer Essentials (8 skills)