refactor: flatten Microsoft skills from nested to flat directory structure

Rewrote sync_microsoft_skills.py (v4) to use each SKILL.md's frontmatter
'name' field as the flat directory name under skills/, replacing the nested
skills/official/microsoft/<lang>/<category>/<service>/ hierarchy.

This fixes CI failures caused by the indexing, validation, and catalog
scripts expecting skills/<id>/SKILL.md (depth 1).

Changes:
- Rewrite scripts/sync_microsoft_skills.py for flat output with collision detection
- Update scripts/tests/inspect_microsoft_repo.py for flat name mapping
- Update scripts/tests/test_comprehensive_coverage.py for name uniqueness checks
- Delete skills/official/ nested directory
- Add 129 Microsoft skills as flat directories (e.g. skills/azure-mgmt-botservice-dotnet/)
- Move attribution files to docs/ (LICENSE-MICROSOFT, microsoft-skills-attribution.json)
- Rebuild skills_index.json, CATALOG.md, README.md (845 total skills)

skills/wiki-qa/SKILL.md

@@ -0,0 +1,34 @@
+---
+name: wiki-qa
+description: Answers questions about a code repository using source file analysis. Use when the user asks a question about how something works, wants to understand a component, or needs help navigating the codebase.
+---
+
+# Wiki Q&A
+
+Answer repository questions grounded entirely in source code evidence.
+
+## When to Activate
+
+- User asks a question about the codebase
+- User wants to understand a specific file, function, or component
+- User asks "how does X work" or "where is Y defined"
+
+## Procedure
+
+1. Detect the language of the question; respond in the same language
+2. Search the codebase for relevant files
+3. Read those files to gather evidence
+4. Synthesize an answer with inline citations
+
+## Response Format
+
+- Use `##` headings, code blocks with language tags, tables, bullet lists
+- Cite sources inline: `(src/path/file.ts:42)`
+- Include a "Key Files" table mapping files to their roles
+- If information is insufficient, say so and suggest files to examine
+
+## Rules
+
+- ONLY use information from actual source files
+- NEVER invent, guess, or use external knowledge
+- Think step by step before answering