chore(cli): update Speakeasy OpenAPI generator to v2.950.8

Sync `third_party/golang/github_com/speakeasy_api/openapi_generation/v/v2` to `https://github.com/speakeasy-api/openapi-generation@c479885` (`v2.950.8`) and regenerate all SDKs (Python, TypeScript, Java, Go, Dotnet, and CLI).

- Require Go 1.26.10 in generated `go.mod` files (`face5cd`).
- Bump Go to 1.26.10 (`5033ab8`).

PiperOrigin-RevId: 1004101989

Author: Google Team Member

.github/workflows/ci.yaml

@@ -10,7 +10,7 @@ permissions:
     contents: read
 
 env:
-    SPEAKEASY_VERSION: v2.950.5
+    SPEAKEASY_VERSION: v2.950.8
 
 jobs:
     non-live-validation:

go.mod

@@ -1,6 +1,6 @@
 module github.com/google-gemini/gemini-api-cli
 
-go 1.26.8
+go 1.26.10
 
 require (
 	charm.land/bubbles/v2 v2.2.1