Initial commit: BLIGHT: CUE

Webhook listener that monitors Gitea repos for BLIGHT: triggers in
markdown files, processes them via Gemini 2.5 Flash-Lite, and writes
results back in-place.

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

ai/base.py

@@ -0,0 +1,21 @@
+from abc import ABC, abstractmethod
+
+
+class AIProvider(ABC):
+    """Base class for all AI provider implementations.
+
+    To add a new provider, subclass this and implement `complete`, then
+    instantiate your provider in `processor.py` instead of GeminiProvider.
+    """
+
+    @abstractmethod
+    def complete(self, document: str, instruction: str) -> str:
+        """Process an instruction in the context of a full document.
+
+        Args:
+            document: The full markdown document text (for context).
+            instruction: The BLIGHT instruction extracted from the trigger line.
+
+        Returns:
+            The text to insert in place of the trigger line.
+        """