Add issue-resolver agent with multi-model analysis and reusable skills

[sheiksyedm]

Description of Change

No automated issue-resolution workflow existed for this repository. Each issue required manual investigation, branch setup, implementation, and reporting — with no enforced structure, no reusable patterns, and no safeguards against mistakes like committing to main or adding unwanted tests.

Introduces a custom GitHub Copilot agent (issue-resolver) and two reusable skills to automate end-to-end issue resolution in a structured, safe, and repeatable way. The reference is taken from the maui repo.

New files added:

.github/agents/issue-resolver.md -> 3-phase agent: Pre-Flight → Fix → Report
.github/skills/multi-model-analysis/SKILL.md -> Reusable skill: runs 3 AI models in parallel to pick the best fix approach
.github/skills/testing-guide/SKILL.md -> Reusable skill: guides test writing, naming conventions, and build/run verification
.github/copilot-instructions.md -> Repo-level Copilot context (project structure, coding style, Git rules)

Agent highlights:

• Phase 1 (Pre-Flight): Gathers issue/PR context, reviewer feedback, edge cases, and file classification — strictly no code analysis until Phase 2
• Phase 2 (Fix): Default model analysis first; optional multi-model review (user permission required); implements the fix; builds and verifies existing tests pass
• Phase 3 (Report): Writes a final structured report to the state file — no commits, pushes, or PRs without explicit user approval
• 13 Critical Rules enforce safe defaults: no direct commits to main, no test additions by default, no git destructive ops, and explicit user approval required before any commit/push/PR

Skills are standalone-invocable — they can be called directly or from any future agent (e.g., a PR review agent or test agent).

[Copilot]

Pull request overview

This PR introduces a structured, reusable GitHub Copilot “issue-resolver” agent plus two standalone skills (multi-model analysis and testing guidance), and adds repo-level Copilot instructions tailored to the Syncfusion .NET MAUI Toolkit workflow and conventions.

Changes:

• Added an end-to-end 3-phase issue-resolver agent definition (Pre-flight → Fix → Report) with safety rules and a state-file workflow.
• Added two reusable skills: multi-model-analysis (parallel model proposals + rubric selection) and testing-guide (test guidance + verification steps).
• Added .github/copilot-instructions.md documenting repo structure, build/test workflow, style, and PR/git rules for Copilot.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
.github/agents/issue-resolver.md	Defines the issue-resolver agent workflow, rules, and state-file reporting format.
.github/skills/multi-model-analysis/SKILL.md	Adds a reusable skill to run parallel analyses and select an approach via rubric.
.github/skills/testing-guide/SKILL.md	Adds a reusable skill describing test location, naming, “what to test”, and verification commands.
.github/copilot-instructions.md	Adds repository-wide Copilot context: structure, build/test commands, style, git/PR rules, and delegation policy.

Comments suppressed due to low confidence (1)

.github/skills/testing-guide/SKILL.md:55

• The recommended test naming convention (MethodOrProperty_Scenario_ExpectedBehavior) doesn’t match existing test patterns in this repo (e.g., IsVisible_SetValue_ReturnsExpectedValue in maui/tests/.../ChartAxisUnitTests.cs). Consider updating the guidance to match the established convention so new tests stay consistent.

**Naming convention**: `MethodOrProperty_Scenario_ExpectedBehavior`

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

[Copilot]

Critical Rule #5 forbids running git checkout / git switch, but Phase 1 Step 5 instructs git checkout -b .... This is internally inconsistent and will cause the agent to violate its own rules. Either allow branch creation as an explicit exception (e.g., permit git checkout -b / git switch -c only for creating the feature branch) or update the Step 5 command to match the allowed git operations.

Suggested change

	5. **Never run `git checkout`, `git switch`, `git stash`, `git reset`** — Create a new branch or use `gh pr checkout`. The agent is always on the correct branch.
	5. **Never run `git checkout`, `git switch`, `git stash`, `git reset`** — except when explicitly instructed to create a new feature branch using `git checkout -b ...` or `git switch -c ...`. Otherwise, create a new branch via other allowed means or use `gh pr checkout`. The agent is always on the correct branch.

[Copilot]

@PaulAndersonS I've opened a new pull request, #335, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

@PaulAndersonS I've opened a new pull request, #336, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

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

[Copilot]

Pull request overview

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

---

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

[Copilot]

Pull request overview

Copilot reviewed 4 out of 5 changed files in this pull request and generated 3 comments.

---

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

[Copilot]

@PaulAndersonS I've opened a new pull request, #337, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

@PaulAndersonS I've opened a new pull request, #338, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

.github/agents/issue-resolver.md:91

• The state file template is written in an issue-centric format (# Issue Resolver State — #XXXXX, issue URL, Number: #XXXXX). Earlier you allow user-prompt driven tasks with a slug instead of an issue number, but the template doesn’t say what to put in these issue-specific fields for that case. Consider adding a short note (or alternative template) for non-issue tasks (e.g., set Number/URL to N/A and adjust the header) to prevent inconsistent state files.

```markdown
# Issue Resolver State — #XXXXX

## Status
| Phase | Status |
|-------|--------|
| 0 — State File | ✅ CREATED |
| 1 — Pre-flight | ⏳ IN PROGRESS |
| 2 — Fix | ⏳ PENDING |
| 3 — Report | ⏳ PENDING |

## Issue
- **Number**: #XXXXX
- **Title**: (fill after fetch)
- **URL**: https://github.com/syncfusion/maui-toolkit/issues/XXXXX
- **Labels**: (fill after fetch)

---

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

[Copilot]

@PaulAndersonS I've opened a new pull request, #339, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 5 changed files in this pull request and generated 4 comments.

---

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

[Copilot]

Critical Rule #8 requires always including an issue number in commit messages (e.g., Fixes #XXXXX), but the agent also explicitly supports user-prompt-driven tasks with no issue number (state file uses a kebab-case slug). Please clarify the commit message rule for non-issue work (e.g., allow omitting Fixes # or using a Refs: line with the slug).