feat: Add SSH key authentication and custom port support (#97)

* feat: Add SSH key authentication and custom port support

- Add SSH key authentication support with three modes: password, key, or both
- Add custom SSH port support (defaults to 22)
- Create SSHKeyInput component with file upload and paste modes
- Update database schema with auth_type, ssh_key, ssh_key_passphrase, and ssh_port columns
- Update TypeScript interfaces to support new authentication fields
- Update SSH services to handle key authentication and custom ports
- Update ServerForm with authentication type selection and SSH port field
- Update API routes with validation for new fields
- Add proper cleanup for temporary SSH key files
- Support for encrypted SSH keys with passphrase protection
- Maintain backward compatibility with existing password-only servers

* fix: Resolve TypeScript build errors and improve type safety

- Replace || operators with ?? (nullish coalescing) for better type safety
- Add proper null checks for password fields in SSH services
- Fix JSDoc type annotations for better TypeScript inference
- Update error object types to use Record<keyof CreateServerData, string>
- Ensure all SSH authentication methods handle optional fields correctly

src/types/server.ts

@@ -3,7 +3,11 @@ export interface Server {
   name: string;
   ip: string;
   user: string;
-  password: string;
+  password?: string;
+  auth_type?: 'password' | 'key' | 'both';
+  ssh_key?: string;
+  ssh_key_passphrase?: string;
+  ssh_port?: number;
   created_at: string;
   updated_at: string;
 }
@@ -12,7 +16,11 @@ export interface CreateServerData {
   name: string;
   ip: string;
   user: string;
-  password: string;
+  password?: string;
+  auth_type?: 'password' | 'key' | 'both';
+  ssh_key?: string;
+  ssh_key_passphrase?: string;
+  ssh_port?: number;
 }
 
 export interface UpdateServerData extends CreateServerData {