chore: Add multi-workflow Copilot review instructions and slim copilot-instructions.md

[Copilot]

copilot-instructions.md duplicated content already in AGENTS.md, and there were no reviewer-specific instructions for code review.

Changes

• .github/copilot-instructions.md — replaced entire content with a single reference to AGENTS.md
• .github/copilot-review-instructions.md — describes a four-pass review workflow (Systems Architect → UI/UX → Code Quality → Test Reviewer); references individual instruction files
• .github/instructions/architecture.instructions.md — applyTo Python/TS/JS/workflow files; checks plugin boundary (server ↔ JS), abstraction level, and CI validation order
• .github/instructions/ui-ux.instructions.md — applyTo TSX/JSX/SCSS/CSS; labels, var(--dh-color-*) token usage, accessibility, interaction model
• .github/instructions/code-quality.instructions.md — applyTo Python/TS/JS; patterns, precise types, error handling, duplication
• .github/instructions/tests.instructions.md — applyTo source + test files + jest/playwright configs; unit, e2e, and full CI validation order

[mofojed]

@copilot will you actually spawn multiple agents to do specialized reviews? Or give more details on how you'll process these instructions when a PR is opened

[Copilot]

I clarified this in .github/copilot-review-instructions.md in commit a4a11aaa: the four passes are a structured review process (specialized lenses), not a strict requirement to spawn separate runtime agents. I also documented the exact PR-open flow: load AGENTS.md, map changed files to the relevant instruction files, run only applicable passes in order, then publish one consolidated set of high-signal findings.

[Copilot]

Pull request overview

This PR restructures repository-level Copilot guidance by moving setup/validation information to AGENTS.md and introducing a multi-pass, reviewer-oriented instruction set intended to improve the quality and relevance of automated PR reviews.

Changes:

• Replaced .github/copilot-instructions.md content with a pointer to AGENTS.md to avoid duplicated setup/validation guidance.
• Added .github/copilot-review-instructions.md describing a four-pass review workflow and referencing specialized instruction files.
• Introduced specialized instruction files for architecture, UI/UX, code quality, and test review scoping.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
.github/copilot-instructions.md	Replaced detailed instructions with a reference to AGENTS.md.
.github/copilot-review-instructions.md	Added multi-pass review workflow guidance and pointers to specialized instruction files.
.github/instructions/architecture.instructions.md	Added architecture-focused review guidance and file scoping for relevant code/workflows.
.github/instructions/code-quality.instructions.md	Added code-quality review guidance scoped to plugin source files.
.github/instructions/tests.instructions.md	Added test-review guidance and documented repo validation order.
.github/instructions/ui-ux.instructions.md	Added UI/UX-focused review guidance scoped to UI and styling files.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.