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-keyvault-secrets-rust/SKILL.md

@@ -0,0 +1,142 @@
+---
+name: azure-keyvault-secrets-rust
+description: |
+  Azure Key Vault Secrets SDK for Rust. Use for storing and retrieving secrets, passwords, and API keys.
+  Triggers: "keyvault secrets rust", "SecretClient rust", "get secret rust", "set secret rust".
+package: azure_security_keyvault_secrets
+---
+
+# Azure Key Vault Secrets SDK for Rust
+
+Client library for Azure Key Vault Secrets — secure storage for passwords, API keys, and other secrets.
+
+## Installation
+
+```sh
+cargo add azure_security_keyvault_secrets azure_identity
+```
+
+## Environment Variables
+
+```bash
+AZURE_KEYVAULT_URL=https://<vault-name>.vault.azure.net/
+```
+
+## Authentication
+
+```rust
+use azure_identity::DeveloperToolsCredential;
+use azure_security_keyvault_secrets::SecretClient;
+
+let credential = DeveloperToolsCredential::new(None)?;
+let client = SecretClient::new(
+    "https://<vault-name>.vault.azure.net/",
+    credential.clone(),
+    None,
+)?;
+```
+
+## Core Operations
+
+### Get Secret
+
+```rust
+let secret = client
+    .get_secret("secret-name", None)
+    .await?
+    .into_model()?;
+
+println!("Secret value: {:?}", secret.value);
+```
+
+### Set Secret
+
+```rust
+use azure_security_keyvault_secrets::models::SetSecretParameters;
+
+let params = SetSecretParameters {
+    value: Some("secret-value".into()),
+    ..Default::default()
+};
+
+let secret = client
+    .set_secret("secret-name", params.try_into()?, None)
+    .await?
+    .into_model()?;
+```
+
+### Update Secret Properties
+
+```rust
+use azure_security_keyvault_secrets::models::UpdateSecretPropertiesParameters;
+use std::collections::HashMap;
+
+let params = UpdateSecretPropertiesParameters {
+    content_type: Some("text/plain".into()),
+    tags: Some(HashMap::from([("env".into(), "prod".into())])),
+    ..Default::default()
+};
+
+client
+    .update_secret_properties("secret-name", params.try_into()?, None)
+    .await?;
+```
+
+### Delete Secret
+
+```rust
+client.delete_secret("secret-name", None).await?;
+```
+
+### List Secrets
+
+```rust
+use azure_security_keyvault_secrets::ResourceExt;
+use futures::TryStreamExt;
+
+let mut pager = client.list_secret_properties(None)?.into_stream();
+while let Some(secret) = pager.try_next().await? {
+    let name = secret.resource_id()?.name;
+    println!("Secret: {}", name);
+}
+```
+
+### Get Specific Version
+
+```rust
+use azure_security_keyvault_secrets::models::SecretClientGetSecretOptions;
+
+let options = SecretClientGetSecretOptions {
+    secret_version: Some("version-id".into()),
+    ..Default::default()
+};
+
+let secret = client
+    .get_secret("secret-name", Some(options))
+    .await?
+    .into_model()?;
+```
+
+## Best Practices
+
+1. **Use Entra ID auth** — `DeveloperToolsCredential` for dev, `ManagedIdentityCredential` for production
+2. **Use `into_model()?`** — to deserialize responses
+3. **Use `ResourceExt` trait** — for extracting names from IDs
+4. **Handle soft delete** — deleted secrets can be recovered within retention period
+5. **Set content type** — helps identify secret format
+6. **Use tags** — for organizing and filtering secrets
+7. **Version secrets** — new values create new versions automatically
+
+## RBAC Permissions
+
+Assign these Key Vault roles:
+- `Key Vault Secrets User` — get and list
+- `Key Vault Secrets Officer` — full CRUD
+
+## Reference Links
+
+| Resource | Link |
+|----------|------|
+| API Reference | https://docs.rs/azure_security_keyvault_secrets |
+| Source Code | https://github.com/Azure/azure-sdk-for-rust/tree/main/sdk/keyvault/azure_security_keyvault_secrets |
+| crates.io | https://crates.io/crates/azure_security_keyvault_secrets |