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-steering-custom/SKILL.md

@@ -0,0 +1,145 @@
+---
+name: kiro-steering-custom
+description: Create custom steering documents for specialized project contexts
+metadata:
+  shared-rules: "steering-principles.md"
+---
+
+
+# Kiro Custom Steering Creation
+
+<background_information>
+**Role**: Create specialized steering documents beyond core files (product, tech, structure).
+
+**Mission**: Help users create domain-specific project memory for specialized areas.
+
+**Success Criteria**:
+- Custom steering captures specialized patterns
+- Follows same granularity principles as core steering
+- Provides clear value for specific domain
+</background_information>
+
+<instructions>
+### Step 1: Gather Context
+
+If steering context is already available from conversation, skip redundant file reads.
+Otherwise:
+- Check `.kiro/settings/templates/steering-custom/` for available templates
+- Read `rules/steering-principles.md` from this skill's directory for steering principles
+
+## Workflow
+
+1. **Ask user** for custom steering needs:
+   - Domain/topic (e.g., "API standards", "testing approach")
+   - Specific requirements or patterns to document
+
+2. **Check if template exists**:
+   - Load from `.kiro/settings/templates/steering-custom/{name}.md` if available
+   - Use as starting point, customize based on project
+
+3. **Analyze codebase** (JIT) for relevant patterns:
+
+#### Parallel Research
+
+The following research areas are independent and can be executed in parallel:
+1. **Template & principles**: Load matching template and steering-principles.md
+2. **Domain patterns**: Analyze codebase for domain-specific patterns using Glob/Grep/Read
+
+If multi-agent is enabled, spawn sub-agents for each area above. Otherwise execute sequentially.
+
+After all parallel research completes, synthesize findings for steering document.
+
+4. **Generate custom steering**:
+   - Follow template structure if available
+   - Apply principles from `rules/steering-principles.md` from this skill's directory
+   - Focus on patterns, not exhaustive lists
+   - Keep to 100-200 lines (2-3 minute read)
+
+5. **Create file** in `.kiro/steering/{name}.md`
+
+## Available Templates
+
+Templates available in `.kiro/settings/templates/steering-custom/`:
+
+1. **api-standards.md** - REST/GraphQL conventions, error handling
+2. **testing.md** - Test organization, mocking, coverage
+3. **security.md** - Auth patterns, input validation, secrets
+4. **database.md** - Schema design, migrations, query patterns
+5. **error-handling.md** - Error types, logging, retry strategies
+6. **authentication.md** - Auth flows, permissions, session management
+7. **deployment.md** - CI/CD, environments, rollback procedures
+
+Load template when needed, customize for project.
+
+## Steering Principles
+
+From `rules/steering-principles.md` (in this skill's directory):
+
+- **Patterns over lists**: Document patterns, not every file/component
+- **Single domain**: One topic per file
+- **Concrete examples**: Show patterns with code
+- **Maintainable size**: 100-200 lines typical
+- **Security first**: Never include secrets or sensitive data
+
+</instructions>
+
+## Tool guidance
+
+- **Read**: Load template, analyze existing code
+- **Glob**: Find related files for pattern analysis
+- **Grep**: Search for specific patterns
+- **Bash** with `ls`: Understand relevant structure
+
+**JIT Strategy**: Load template only when creating that type of steering.
+
+## Output description
+
+Chat summary with file location (file created directly).
+
+```
+✅ Custom Steering Created
+
+## Created:
+- .kiro/steering/api-standards.md
+
+## Based On:
+- Template: api-standards.md
+- Analyzed: src/api/ directory patterns
+- Extracted: REST conventions, error format
+
+## Content:
+- Endpoint naming patterns
+- Request/response format
+- Error handling conventions
+- Authentication approach
+
+Review and customize as needed.
+```
+
+## Examples
+
+### Success: API Standards
+**Input**: "Create API standards steering"  
+**Action**: Load template, analyze src/api/, extract patterns  
+**Output**: api-standards.md with project-specific REST conventions
+
+### Success: Testing Strategy
+**Input**: "Document our testing approach"  
+**Action**: Load template, analyze test files, extract patterns  
+**Output**: testing.md with test organization and mocking strategies
+
+## Safety & Fallback
+
+- **No template**: Generate from scratch based on domain knowledge
+- **Security**: Never include secrets (load principles)
+- **Validation**: Ensure doesn't duplicate core steering content
+
+## Notes
+
+- Templates are starting points, customize for project
+- Follow same granularity principles as core steering
+- All steering files loaded as project memory
+- Custom files equally important as core files
+- Avoid documenting agent-specific tooling directories (e.g. `.cursor/`, `.gemini/`, `.claude/`)
+- Light references to `.kiro/specs/` and `.kiro/steering/` are acceptable; avoid other `.kiro/` directories
+