feat(models): add configuration and lock models for patch management

- Introduce models for managing upstream and patch configurations.
- Add lock models to track the last processed upstream commit.
- Enable structured data validation using Pydantic.

src/patchman/models/config.py

@@ -0,0 +1,16 @@
+from typing import Optional
+from pydantic import BaseModel, Field, HttpUrl
+
+
+class UpstreamConfig(BaseModel):
+    url: HttpUrl = Field(..., description="Git URL of the upstream repository")
+    branch: str = Field(default="main", description="Upstream branch to track (default: 'main')")
+
+
+class PatchesConfig(BaseModel):
+    directory: str = Field(default="./patches", description="Path to patch directory")
+
+
+class PatchmanConfig(BaseModel):
+    upstream: UpstreamConfig
+    patches: PatchesConfig

src/patchman/models/lock.py

@@ -0,0 +1,11 @@
+from pydantic import BaseModel, Field
+from typing import Literal
+
+
+class UpstreamLock(BaseModel):
+    last_commit: str = Field(..., min_length=40, max_length=40, pattern="^[0-9a-f]{40}$",
+                             description="Commit hash of the last processed upstream repository")
+
+
+class PatchmanLock(BaseModel):
+    upstream: UpstreamLock