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-keys-rust/SKILL.md

@@ -0,0 +1,167 @@
+---
+name: azure-keyvault-keys-rust
+description: |
+  Azure Key Vault Keys SDK for Rust. Use for creating, managing, and using cryptographic keys.
+  Triggers: "keyvault keys rust", "KeyClient rust", "create key rust", "encrypt rust", "sign rust".
+package: azure_security_keyvault_keys
+---
+
+# Azure Key Vault Keys SDK for Rust
+
+Client library for Azure Key Vault Keys — secure storage and management of cryptographic keys.
+
+## Installation
+
+```sh
+cargo add azure_security_keyvault_keys azure_identity
+```
+
+## Environment Variables
+
+```bash
+AZURE_KEYVAULT_URL=https://<vault-name>.vault.azure.net/
+```
+
+## Authentication
+
+```rust
+use azure_identity::DeveloperToolsCredential;
+use azure_security_keyvault_keys::KeyClient;
+
+let credential = DeveloperToolsCredential::new(None)?;
+let client = KeyClient::new(
+    "https://<vault-name>.vault.azure.net/",
+    credential.clone(),
+    None,
+)?;
+```
+
+## Key Types
+
+| Type | Description |
+|------|-------------|
+| RSA | RSA keys (2048, 3072, 4096 bits) |
+| EC | Elliptic curve keys (P-256, P-384, P-521) |
+| RSA-HSM | HSM-protected RSA keys |
+| EC-HSM | HSM-protected EC keys |
+
+## Core Operations
+
+### Get Key
+
+```rust
+let key = client
+    .get_key("key-name", None)
+    .await?
+    .into_model()?;
+
+println!("Key ID: {:?}", key.key.as_ref().map(|k| &k.kid));
+```
+
+### Create Key
+
+```rust
+use azure_security_keyvault_keys::models::{CreateKeyParameters, KeyType};
+
+let params = CreateKeyParameters {
+    kty: KeyType::Rsa,
+    key_size: Some(2048),
+    ..Default::default()
+};
+
+let key = client
+    .create_key("key-name", params.try_into()?, None)
+    .await?
+    .into_model()?;
+```
+
+### Create EC Key
+
+```rust
+use azure_security_keyvault_keys::models::{CreateKeyParameters, KeyType, CurveName};
+
+let params = CreateKeyParameters {
+    kty: KeyType::Ec,
+    curve: Some(CurveName::P256),
+    ..Default::default()
+};
+
+let key = client
+    .create_key("ec-key", params.try_into()?, None)
+    .await?
+    .into_model()?;
+```
+
+### Delete Key
+
+```rust
+client.delete_key("key-name", None).await?;
+```
+
+### List Keys
+
+```rust
+use azure_security_keyvault_keys::ResourceExt;
+use futures::TryStreamExt;
+
+let mut pager = client.list_key_properties(None)?.into_stream();
+while let Some(key) = pager.try_next().await? {
+    let name = key.resource_id()?.name;
+    println!("Key: {}", name);
+}
+```
+
+### Backup Key
+
+```rust
+let backup = client.backup_key("key-name", None).await?;
+// Store backup.value safely
+```
+
+### Restore Key
+
+```rust
+use azure_security_keyvault_keys::models::RestoreKeyParameters;
+
+let params = RestoreKeyParameters {
+    key_bundle_backup: backup_bytes,
+};
+
+client.restore_key(params.try_into()?, None).await?;
+```
+
+## Cryptographic Operations
+
+Key Vault can perform crypto operations without exposing the private key:
+
+```rust
+// For cryptographic operations, use the key's operations
+// Available operations depend on key type and permissions:
+// - encrypt/decrypt (RSA)
+// - sign/verify (RSA, EC)
+// - wrapKey/unwrapKey (RSA)
+```
+
+## Best Practices
+
+1. **Use Entra ID auth** — `DeveloperToolsCredential` for dev, `ManagedIdentityCredential` for production
+2. **Use HSM keys for sensitive workloads** — hardware-protected keys
+3. **Use EC for signing** — more efficient than RSA
+4. **Use RSA for encryption** — when encrypting data
+5. **Backup keys** — for disaster recovery
+6. **Enable soft delete** — required for production vaults
+7. **Use key rotation** — create new versions periodically
+
+## RBAC Permissions
+
+Assign these Key Vault roles:
+- `Key Vault Crypto User` — use keys for crypto operations
+- `Key Vault Crypto Officer` — full CRUD on keys
+
+## Reference Links
+
+| Resource | Link |
+|----------|------|
+| API Reference | https://docs.rs/azure_security_keyvault_keys |
+| Source Code | https://github.com/Azure/azure-sdk-for-rust/tree/main/sdk/keyvault/azure_security_keyvault_keys |
+| crates.io | https://crates.io/crates/azure_security_keyvault_keys |