chore: add kiro spec-driven tooling and steering docs

Add the Kiro-style agentic SDLC tooling used to drive this project: the
.opencode/skills/kiro-* skill set (discovery, spec init/requirements/design/
tasks, validation, implementation, review, steering), the .kiro/settings
templates, and AGENTS.md describing the workflow. Update the spec docs
(assessment/design/requirements/tasks) to current state.

Scope tests/test_opencode_skills.py to the project's own openultrasast-*
skills so the third-party kiro-* tooling (which uses a different frontmatter
convention) no longer breaks the frontmatter check.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

.opencode/skills/kiro-spec-design/rules/design-discovery-full.md

@@ -0,0 +1,93 @@
+# Full Discovery Process for Technical Design
+
+## Objective
+Conduct comprehensive research and analysis to ensure the technical design is based on complete, accurate, and up-to-date information.
+
+## Discovery Steps
+
+### 1. Requirements Analysis
+**Map Requirements to Technical Needs**
+- Extract all functional requirements from EARS format
+- Identify non-functional requirements (performance, security, scalability)
+- Determine technical constraints and dependencies
+- List core technical challenges
+
+### 2. Existing Implementation Analysis
+**Understand Current System** (if modifying/extending):
+- Analyze codebase structure and architecture patterns
+- Map reusable components, services, utilities
+- Identify domain boundaries and data flows
+- Document integration points and dependencies
+- Determine approach: extend vs refactor vs wrap
+
+### 3. Technology Research
+**Investigate Best Practices and Solutions**:
+- **Use WebSearch** to find:
+  - Latest architectural patterns for similar problems
+  - Industry best practices for the technology stack
+  - Recent updates or changes in relevant technologies
+  - Common pitfalls and solutions
+
+- **Use WebFetch** to analyze:
+  - Official documentation for frameworks/libraries
+  - API references and usage examples
+  - Migration guides and breaking changes
+  - Performance benchmarks and comparisons
+
+### 4. External Dependencies Investigation
+**For Each External Service/Library**:
+- Search for official documentation and GitHub repositories
+- Verify API signatures and authentication methods
+- Check version compatibility with existing stack
+- Investigate rate limits and usage constraints
+- Find community resources and known issues
+- Document security considerations
+- Note any gaps requiring implementation investigation
+
+### 5. Architecture Pattern & Boundary Analysis
+**Evaluate Architectural Options**:
+- Compare relevant patterns (MVC, Clean, Hexagonal, Event-driven)
+- Assess fit with existing architecture and steering principles
+- Identify domain boundaries and ownership seams required to avoid team conflicts
+- Consider scalability implications and operational concerns
+- Evaluate maintainability and team expertise
+- Document preferred pattern and rejected alternatives in `research.md`
+
+### 6. Risk Assessment
+**Identify Technical Risks**:
+- Performance bottlenecks and scaling limits
+- Security vulnerabilities and attack vectors
+- Integration complexity and coupling
+- Technical debt creation vs resolution
+- Knowledge gaps and training needs
+
+## Research Guidelines
+
+### When to Search
+**Always search for**:
+- External API documentation and updates
+- Security best practices for authentication/authorization
+- Performance optimization techniques for identified bottlenecks
+- Latest versions and migration paths for dependencies
+
+**Search if uncertain about**:
+- Architectural patterns for specific use cases
+- Industry standards for data formats/protocols
+- Compliance requirements (GDPR, HIPAA, etc.)
+- Scalability approaches for expected load
+
+### Search Strategy
+1. Start with official sources (documentation, GitHub)
+2. Check recent blog posts and articles (last 6 months)
+3. Review Stack Overflow for common issues
+4. Investigate similar open-source implementations
+
+## Output Requirements
+Capture all findings that impact design decisions in `research.md` using the shared template:
+- Key insights affecting architecture, technology alignment, and contracts
+- Constraints discovered during research
+- Recommended approaches and selected architecture pattern with rationale
+- Rejected alternatives and trade-offs (documented in the Design Decisions section)
+- Updated domain boundaries that inform Components & Interface Contracts
+- Risks and mitigation strategies
+- Gaps requiring further investigation during implementation