Implement direct SSH key generation with ssh2 native API

- Replace complex PEM-to-SSH conversion logic with ssh2's generateKeyPairSync
- Add three key generation buttons: Ed25519, ECDSA P-256, and RSA
- Generate keys directly in SSH format (ssh-ed25519, ecdsa-sha2-nistp256, ssh-rsa)
- Fix ECDSA parameter bug: use bits (256) instead of curve for ssh2 API
- Enhance generate-public-key endpoint with SSH format conversion
- Add comprehensive key type detection and parsing fallbacks
- Add internationalization support for key generation UI
- Simplify codebase from 300+ lines to ~80 lines of clean SSH generation

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/locales/en/translation.json

@@ -143,7 +143,14 @@
     "publicKeyGeneratedSuccessfully": "Public key generated successfully",
     "detectedKeyType": "Detected key type",
     "detectingKeyType": "detecting...",
-    "optional": "Optional"
+    "optional": "Optional",
+    "generateKeyPair": "Generate New Key Pair",
+    "generateEd25519": "Generate Ed25519",
+    "generateECDSA": "Generate ECDSA",
+    "generateRSA": "Generate RSA",
+    "keyPairGeneratedSuccessfully": "{{keyType}} key pair generated successfully",
+    "failedToGenerateKeyPair": "Failed to generate key pair",
+    "generateKeyPairNote": "Generate a new SSH key pair directly. This will replace any existing keys in the form."
   },
   "sshTools": {
     "title": "SSH Tools",