poe: add Gemini-3.1-Pro and update Claude Sonnet 4.6

Author: fhennerkes

providers/poe/models/anthropic/claude-sonnet-4.6.toml

@@ -18,5 +18,5 @@ context = 983_040
 output = 128_000
 
 [modalities]
-input = ["text", "pdf"]
+input = ["text", "image", "pdf"]
 output = ["text"]

providers/poe/models/google/gemini-3.1-pro.toml

@@ -0,0 +1,21 @@
+name = "Gemini-3.1-Pro"
+release_date = "2026-02-19"
+last_updated = "2026-02-19"
+attachment = true
+reasoning = true
+temperature = false
+open_weights = false
+tool_call = true
+
+[cost]
+input = 2
+output = 12
+cache_read = 0.2
+
+[limit]
+context = 1_048_576
+output = 65_536
+
+[modalities]
+input = ["text", "image", "video", "audio"]
+output = ["text"]