fix: [Price] Wrong price for google/gemini-3.6-flash, for Google provider

providers/google/models/gemini-3.6-flash.toml

@@ -1,6 +1,8 @@
 # Sources:
-# - https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-6-flash-3-5-flash-lite-3-5-flash-cyber/
-# - https://ai.google.dev/gemini-api/docs/pricing
+# - https://ai.google.dev/gemini-api/docs/pricing#gemini-3.6-flash
+# Introductory Standard paid tier through 2026-12-31: $0.75/$3.75 (input/output);
+# $0.075 cache read. Reverts to $1.50/$7.50 and $0.15 cache from 2027-01-01.
+# Input (text/image/video/audio) shares the input rate on the pricing page.
 base_model = "google/gemini-3.6-flash"
 
 [[reasoning_options]]
@@ -8,7 +10,7 @@ type = "effort"
 values = ["minimal", "low", "medium", "high"]
 
 [cost]
-input = 1.50
-output = 7.50
-cache_read = 0.15
-input_audio = 1.50
+input = 0.75
+output = 3.75
+cache_read = 0.075
+input_audio = 0.75