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/azure-communication-callingserver-java/SKILL.md

@@ -0,0 +1,91 @@
+---
+name: azure-communication-callingserver-java
+description: Azure Communication Services CallingServer (legacy) Java SDK. Note - This SDK is deprecated. Use azure-communication-callautomation instead for new projects. Only use this skill when maintaining legacy code.
+package: com.azure:azure-communication-callingserver
+---
+
+# Azure Communication CallingServer (Java) - DEPRECATED
+
+> **⚠️ DEPRECATED**: This SDK has been renamed to **Call Automation**. For new projects, use `azure-communication-callautomation` instead. This skill is for maintaining legacy code only.
+
+## Migration to Call Automation
+
+```xml
+<!-- OLD (deprecated) -->
+<dependency>
+    <groupId>com.azure</groupId>
+    <artifactId>azure-communication-callingserver</artifactId>
+    <version>1.0.0-beta.5</version>
+</dependency>
+
+<!-- NEW (use this instead) -->
+<dependency>
+    <groupId>com.azure</groupId>
+    <artifactId>azure-communication-callautomation</artifactId>
+    <version>1.6.0</version>
+</dependency>
+```
+
+## Class Name Changes
+
+| CallingServer (Old) | Call Automation (New) |
+|---------------------|----------------------|
+| `CallingServerClient` | `CallAutomationClient` |
+| `CallingServerClientBuilder` | `CallAutomationClientBuilder` |
+| `CallConnection` | `CallConnection` (same) |
+| `ServerCall` | Removed - use `CallConnection` |
+
+## Legacy Client Creation
+
+```java
+// OLD WAY (deprecated)
+import com.azure.communication.callingserver.CallingServerClient;
+import com.azure.communication.callingserver.CallingServerClientBuilder;
+
+CallingServerClient client = new CallingServerClientBuilder()
+    .connectionString("<connection-string>")
+    .buildClient();
+
+// NEW WAY
+import com.azure.communication.callautomation.CallAutomationClient;
+import com.azure.communication.callautomation.CallAutomationClientBuilder;
+
+CallAutomationClient client = new CallAutomationClientBuilder()
+    .connectionString("<connection-string>")
+    .buildClient();
+```
+
+## Legacy Recording
+
+```java
+// OLD WAY
+StartRecordingOptions options = new StartRecordingOptions(serverCallId)
+    .setRecordingStateCallbackUri(callbackUri);
+
+StartCallRecordingResult result = client.startRecording(options);
+String recordingId = result.getRecordingId();
+
+client.pauseRecording(recordingId);
+client.resumeRecording(recordingId);
+client.stopRecording(recordingId);
+
+// NEW WAY - see azure-communication-callautomation skill
+```
+
+## For New Development
+
+**Do not use this SDK for new projects.** 
+
+See the `azure-communication-callautomation-java` skill for:
+- Making outbound calls
+- Answering incoming calls
+- Call recording
+- DTMF recognition
+- Text-to-speech / speech-to-text
+- Adding/removing participants
+- Call transfer
+
+## Trigger Phrases
+
+- "callingserver legacy", "deprecated calling SDK"
+- "migrate callingserver to callautomation"