feat: add frontend development guidelines and structure documentation

- Introduced API guidelines for interface contracts and request handling.
- Added design tokens usage guidelines for consistent styling across the project.
- Established DTO guidelines for defining request parameters and response data types.
- Created frontend structure guidelines to clarify directory organization and code placement rules.
- Compiled a comprehensive frontend development guideline document covering various aspects of the development process.
- Implemented quality guidelines to ensure code maintainability and adherence to best practices.

AI-RD-Workflow/20-skills/pm-requirement-review/SKILL.md

@@ -0,0 +1,40 @@
+---
+name: pm-requirement-review
+description: Review raw user or business requirements from a PM perspective. Use when Codex needs to assess whether an intake or user requirement is clear, valuable, scoped, testable, and ready for refinement into requirement analysis and scenario analysis.
+---
+
+# PM Requirement Review
+
+Review the input as a PM before refinement.
+
+## Inputs
+
+- Intake document or raw user request.
+- Existing UR, RA, or SA if available.
+
+## Process
+
+1. Identify the target user, business goal, and triggering problem.
+2. Check whether the requested outcome is measurable.
+3. Separate in-scope, out-of-scope, and unknown items.
+4. Identify missing context, ambiguous terms, hidden assumptions, and decision points.
+5. Check whether acceptance direction can be verified.
+
+## Output
+
+Produce a review note with:
+
+- Summary.
+- Confirmed facts.
+- Ambiguities.
+- Missing information.
+- Scope risks.
+- Scenario gaps.
+- Recommended next questions.
+- Gate decision: `pass`, `pass-with-questions`, or `rework`.
+
+## Constraints
+
+- Do not invent business facts.
+- Mark assumptions explicitly.
+- Prefer concrete questions over broad advice.