docs: realign stale references with current source of truth

[jkim323]

Description

Resolves a batch of documentation drift issues where prose docs and READMEs fell behind code, agent, and path changes from recent PRs. Each fix realigns stale references with the current source of truth:

• BRD/PRD output path move (PR fix: clarify markdownlint marker placement in PRD Builder #2098): updated lifecycle, role, and planning docs to point at docs/project-planning/ instead of the retired docs/brds/ and docs/prds/.
• Eval CI behavior (PRs feat(agents): add Vally evaluation agents and prompts #1834, feat: Improve quality of rpi-agent.agent.md #1949): documented shared-spec tag-aware run behavior, the missing eval npm commands, and the mixed stub mode plus sub-threshold advisory-fail status.
• Copyright tooling (PR chore(scripts): standardize copyright headers to canonical 2026 format #2169): documented the new CopyrightHeader.psm1 module and the Test-CopyrightHeaders.ps1 -Fix switch and canonical 2026 header format.
• Collection helpers (PR feat(agents): add Vally evaluation agents and prompts #1834): documented the new strict-safe maturity vocabulary functions in CollectionHelpers.psm1.
• rai-license-posture.instructions.md‎: fix dead link and added rai-license-posture instruction conformance stimulus to instructions.eval.yml

Related Issue(s)

Closes #2179
Closes #2180
Closes #2181
Closes #2182
Closes #2183
Closes #2187
Closes #2188
Closes #2191

Type of Change

Select all that apply:

Code & Documentation:

• Bug fix (non-breaking change fixing an issue)
• New feature (non-breaking change adding functionality)
• Breaking change (fix or feature causing existing functionality to change)
• Documentation update

Infrastructure & Configuration:

• GitHub Actions workflow
• Linting configuration (markdown, PowerShell, etc.)
• Security configuration
• DevContainer configuration
• Dependency update

AI Artifacts:

• Reviewed contribution with prompt-builder agent and addressed all feedback
• Copilot instructions (.github/instructions/*.instructions.md)
• Copilot prompt (.github/prompts/*.prompt.md)
• Copilot agent (.github/agents/*.agent.md)
• Copilot skill (.github/skills/*/SKILL.md)
• Copilot hook (.github/hooks/*/*.json)
• Eval spec added/updated for changed AI artifacts (evals/)

Other:

• Script/automation (.ps1, .sh, .py)
• Other (please describe):

Testing

Checklist

Required Checks

• Documentation is updated (if applicable)
• Files follow existing naming conventions
• Changes are backwards compatible (if applicable)
• Tests added for new functionality (if applicable) (N/A — documentation-only)

Required Automated Checks

The following validation commands must pass before merging:

• Markdown linting: npm run lint:md
• Spell checking: npm run spell-check
• Frontmatter validation: npm run lint:frontmatter
• Skill structure validation: npm run validate:skills
• Link validation: npm run lint:md-links
• PowerShell analysis: npm run lint:ps
• Plugin freshness: npm run plugin:generate
• Docusaurus tests: npm run docs:test

Security Considerations

• This PR does not contain any sensitive or NDA information
• Any new dependencies have been reviewed for security issues (N/A — no dependency changes)
• Security-related scripts follow the principle of least privilege (N/A — no security scripts modified)

Additional Notes

Documentation-only change. #2186 (DT Coach session-path rename) is deliberately excluded from this batch.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.31%. Comparing base (4640d87) to head (04a03cc).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2220      +/-   ##
==========================================
- Coverage   81.32%   81.31%   -0.01%     
==========================================
  Files         130      130              
  Lines       19140    19140              
  Branches       12       12              
==========================================
- Hits        15565    15564       -1     
- Misses       3572     3573       +1     
  Partials        3        3              

Flag	Coverage Δ
docusaurus	61.84% <ø> (ø)
pester	86.02% <ø> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.
see 1 file with indirect coverage changes

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[github-actions]

Eval Execution

✅ Status: Passed — no merge-blocking failures (2 advisory assertion failure(s) present)

• Artifacts evaluated: 1
• Specs run: 1
• Assertions passed: 1
• Assertions failed (blocking): 0
• Assertions failed (advisory): 2
• Failed specs (merge-blocking): 0

Artifact	Kind	Status	Specs	Passed	Failed (blocking)	Failed (advisory)
rai-license-posture	instruction	⚠️ advisory-fail	1	1	0	2

Legend — ✅ clean · ⚠️ advisory failures only (non-blocking) · ⏭️ skipped · ❌ merge-blocking failure

Only Failed specs (merge-blocking) gates this PR. Advisory assertion failures are signal-quality checks captured during iteration; review them, but they do not block merge and may be acceptable.