Add SSH key generation and deployment features (#234)

* Fix SSH key upload and credential editing issues

Fixed two major credential management issues:

1. Fix SSH key upload button not responding (Issue #232)
   - Error handling was silently swallowing exceptions
   - Added proper error propagation in axios functions
   - Improved error display to show specific error messages
   - Users now see actual error details instead of generic messages

2. Improve credential editing to show actual content
   - Both "Upload File" and "Paste Key" modes now display existing data
   - Upload mode: shows current key content in read-only preview area
   - Paste mode: shows editable key content in textarea
   - Smart input method switching preserves existing data
   - Enhanced button labels and status indicators

Key changes:
- Fixed handleApiError propagation in main-axios.ts credential functions
- Enhanced CredentialEditor.tsx with key content preview
- Improved error handling with console logging for debugging
- Better UX with clear status indicators and preserved data

These fixes resolve the "Add Credential button does nothing" issue
and provide full visibility of credential content during editing.

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

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

* Add comprehensive SSH key management and validation features

- Add support for both private and public key storage
- Implement automatic SSH key type detection for all major formats (RSA, Ed25519, ECDSA, DSA)
- Add real-time key pair validation to verify private/public key correspondence
- Enhance credential editor UI with unified key input interface supporting upload/paste
- Improve file format support including extensionless files (id_rsa, id_ed25519, etc.)
- Add comprehensive fallback detection for OpenSSH format keys
- Implement debounced API calls for better UX during real-time validation
- Update database schema with backward compatibility for existing credentials
- Add API endpoints for key detection and pair validation
- Fix SSH2 module integration issues in TypeScript environment

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

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

* Optimize credentials interface and add i18n improvements

- Merge upload/paste tabs into unified SSH key input interface
- Remove manual key type selection dropdown (rely on auto-detection)
- Add public key generation from private key functionality
- Complete key pair validation removal to fix errors
- Add missing translation keys for better internationalization
- Improve UX with streamlined credential editing workflow

* 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>

* Add passphrase support for SSH key generation

- Add optional passphrase input field in key generation container
- Implement AES-128-CBC encryption for protected private keys
- Auto-fill key password field when passphrase is provided
- Support passphrase protection for all key types (Ed25519, ECDSA, RSA)
- Enhance user experience with automatic form field population

* Implement SSH key deployment feature with credential resolution

- Add SSH key deployment endpoint supporting all authentication types
- Implement automatic credential resolution for credential-based hosts
- Add deployment UI with host selection and progress tracking
- Support password, key, and credential authentication methods
- Include deployment verification and error handling
- Add public key field to credential types and API responses
- Implement secure SSH connection handling with proper timeout

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

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

---------

Co-authored-by: ZacharyZcR <zacharyzcr1984@gmail.com>
Co-authored-by: Claude <noreply@anthropic.com>

src/locales/en/translation.json

@@ -130,7 +130,27 @@
     "folderRenamed": "Folder \"{{oldName}}\" renamed to \"{{newName}}\" successfully",
     "failedToRenameFolder": "Failed to rename folder",
     "movedToFolder": "Credential \"{{name}}\" moved to \"{{folder}}\" successfully",
-    "failedToMoveToFolder": "Failed to move credential to folder"
+    "failedToMoveToFolder": "Failed to move credential to folder",
+    "sshPublicKey": "SSH Public Key",
+    "publicKeyNote": "Public key is optional but recommended for key validation",
+    "publicKeyUploaded": "Public Key Uploaded",
+    "uploadPublicKey": "Upload Public Key",
+    "uploadPrivateKeyFile": "Upload Private Key File",
+    "uploadPublicKeyFile": "Upload Public Key File",
+    "privateKeyRequiredForGeneration": "Private key is required to generate public key",
+    "failedToGeneratePublicKey": "Failed to generate public key",
+    "generatePublicKey": "Generate from Private Key",
+    "publicKeyGeneratedSuccessfully": "Public key generated successfully",
+    "detectedKeyType": "Detected key type",
+    "detectingKeyType": "detecting...",
+    "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",
@@ -878,6 +898,7 @@
     "password": "password",
     "keyPassword": "key password",
     "pastePrivateKey": "Paste your private key here...",
+    "pastePublicKey": "Paste your public key here...",
     "credentialName": "My SSH Server",
     "description": "SSH credential description",
     "searchCredentials": "Search credentials by name, username, or tags...",