feat: complete Git Repo Manager MVP implementation

Backend (Phase 1-6):
- Pydantic schemas for request/response validation
- Service layer (SSH Key, Server, Repo, Sync)
- API routes with authentication
- FastAPI main application with lifespan management
- ORM models (SshKey, Server, Repo, SyncLog)

Frontend (Phase 7):
- Vue 3 + Element Plus + Pinia + Vue Router
- API client with Axios and interceptors
- State management stores
- All page components (Dashboard, Servers, Repos, SyncLogs, SshKeys, Settings)

Deployment (Phase 8):
- README with quick start guide
- Startup script (start.sh)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/schemas/ssh_key.py

@@ -0,0 +1,63 @@
+"""
+SSH Key Pydantic schemas.
+"""
+from typing import Optional
+from pydantic import BaseModel, Field, field_validator
+
+
+class SshKeyCreate(BaseModel):
+    """
+    Schema for creating a new SSH key.
+    """
+    name: str = Field(..., min_length=1, max_length=100, description="SSH key name")
+    private_key: str = Field(..., min_length=1, description="SSH private key content")
+
+    @field_validator("name")
+    @classmethod
+    def name_must_not_be_empty(cls, v: str) -> str:
+        """Validate that name is not empty or whitespace only."""
+        if not v or not v.strip():
+            raise ValueError("name must not be empty")
+        return v.strip()
+
+    @field_validator("private_key")
+    @classmethod
+    def private_key_must_not_be_empty(cls, v: str) -> str:
+        """Validate that private_key is not empty or whitespace only."""
+        if not v or not v.strip():
+            raise ValueError("private_key must not be empty")
+        return v.strip()
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "name": "my-git-key",
+                    "private_key": "-----BEGIN OPENSSH PRIVATE KEY-----\n...\n-----END OPENSSH PRIVATE KEY-----"
+                }
+            ]
+        }
+    }
+
+
+class SshKeyResponse(BaseModel):
+    """
+    Schema for SSH key response.
+    """
+    id: int = Field(description="SSH key ID")
+    name: str = Field(description="SSH key name")
+    fingerprint: Optional[str] = Field(default=None, description="SSH key fingerprint")
+    created_at: int = Field(description="Creation timestamp (Unix timestamp)")
+
+    model_config = {
+        "json_schema_extra": {
+            "examples": [
+                {
+                    "id": 1,
+                    "name": "my-git-key",
+                    "fingerprint": "SHA256:abc123...",
+                    "created_at": 1711804800
+                }
+            ]
+        }
+    }