문서 repair guide와 목적형 HTML/XLSX 경로를 추가 고도화

- ArtifactRepairGuideService를 추가해 HTML/XLSX/DOCX 품질 리뷰 결과를 Repair guide 형태의 실행 가능한 보정 지침으로 변환
- HtmlSkill, ExcelSkill, DocumentAssemblerTool 출력에 repair guide를 연결해 품질 점수 뒤에 후속 보완 방향을 함께 제공
- Excel dashboard sheet에 dashboard_tiles와 variance_series를 추가해 운영 리뷰형 workbook archetype을 강화
- strategy-brief-html, operating-review-xlsx 번들 스킬을 추가해 목적형 문서 생성 진입점을 확장
- README.md와 docs/DEVELOPMENT.md에 2026-04-14 23:58 (KST) 기준 작업 이력과 검증 명령을 반영

검증 결과
- dotnet build src/AxCopilot/AxCopilot.csproj -c Release -v minimal -p:OutputPath=bin\\verify_doc_next6\\ -p:IntermediateOutputPath=obj\\verify_doc_next6\\ : 경고 0 / 오류 0
- dotnet test src/AxCopilot.Tests/AxCopilot.Tests.csproj -c Release -v minimal --filter ArtifactQualityReviewServiceTests|ArtifactRepairGuideServiceTests|ExcelSkillDashboardSummaryTests|HtmlSkillConsultingSectionsTests|HtmlSkillPrintFrameTests|DocumentAssemblerStyleMapTests|DocumentAssemblerDocxFeaturesTests|DocumentAssemblerSemanticTests|PptxSkillGoldenDeckTests|DeckQualityReviewServiceTests -p:OutputPath=bin\\verify_doc_next6_tests\\ -p:IntermediateOutputPath=obj\\verify_doc_next6_tests\\ : 통과 17

src/AxCopilot.Tests/Services/ArtifactRepairGuideServiceTests.cs

@@ -0,0 +1,44 @@
+using AxCopilot.Services.Agent;
+using FluentAssertions;
+using Xunit;
+
+namespace AxCopilot.Tests.Services;
+
+public class ArtifactRepairGuideServiceTests
+{
+    [Fact]
+    public void BuildGuide_ForWorkbookIssues_ShouldReturnWorkbookActions()
+    {
+        var review = new ArtifactQualityReport(
+            "xlsx",
+            68,
+            ["Includes summary sheet"],
+            [
+                new ArtifactReviewIssue("Workbook could benefit from a dashboard sheet to summarize multi-sheet trends.", ArtifactReviewSeverity.Info),
+                new ArtifactReviewIssue("Summary sheet does not link to detail sheets.", ArtifactReviewSeverity.Warning)
+            ]);
+
+        var guide = ArtifactRepairGuideService.BuildGuide(review);
+
+        guide.Should().Contain("dashboard sheet");
+        guide.Should().Contain("detail sheets");
+    }
+
+    [Fact]
+    public void BuildGuide_ForHtmlIssues_ShouldReturnHtmlActions()
+    {
+        var review = new ArtifactQualityReport(
+            "html",
+            70,
+            ["Includes print-ready CSS"],
+            [
+                new ArtifactReviewIssue("Print-ready business report would benefit from decision summary or evidence cards.", ArtifactReviewSeverity.Warning),
+                new ArtifactReviewIssue("Strategy brief would be stronger with a comparison or roadmap block.", ArtifactReviewSeverity.Info)
+            ]);
+
+        var guide = ArtifactRepairGuideService.BuildGuide(review);
+
+        guide.Should().Contain("decision summary");
+        guide.Should().Contain("comparison or roadmap");
+    }
+}