fix(agents): PRD Builder lacks quality gate against implementation-level details leaking into requirements

[manabu-sekino]

Problem

prd-builder.agent.md's "Quality Requirements" and "Final Approval Checklist" sections
do not include a check ensuring functional/non-functional requirements remain
implementation-agnostic. When source material already contains concrete code
(e.g., a completed hi-fi prototype), the agent tends to copy function names,
type names, and file paths directly into Description/Acceptance Criteria fields
instead of abstracting them to outcome-level language.

Example

Given a requirement grounded in an existing prototype, the agent produced:

• FR: "must not change the output of someFunction()"
• Acceptance: "add a type field to SomeType"

These are design/implementation directives, not business requirements, and go
stale as soon as the referenced code is refactored.

Suggested fix

Add an explicit checklist item, e.g.:
"Requirements and acceptance criteria are implementation-agnostic (no function
names, type names, or file paths in Description/Acceptance columns). Concrete
code references belong only in the Notes/evidence column as provenance."

Environment

• Extension: ise-hve-essentials.hve-core-all v3.3.101
• Agent file: .github/agents/project-planning/prd-builder.agent.md