feat(llm): provider factory with per-provider default base URLs

internal/llm/gemini.go

@@ -0,0 +1,24 @@
+package llm
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+)
+
+type geminiClient struct {
+	http       *http.Client
+	base       string
+	key        string
+	model      string
+	audioModel string
+	maxTokens  int
+}
+
+func (c *geminiClient) Vision(_ context.Context, _ string, _ []Image, _ Options) (string, error) {
+	return "", fmt.Errorf("gemini provider not yet implemented")
+}
+
+func (c *geminiClient) Transcribe(_ context.Context, _ []byte, _ string, _ Options) (string, error) {
+	return "", fmt.Errorf("gemini provider not yet implemented")
+}