Drop github_token boilerplate from scenario fixtures

Every scenario explicitly threaded GITHUB_TOKEN from the parent env into
the SDK client options:

  - Python:   github_token=os.environ.get("GITHUB_TOKEN")
  - TypeScript: gitHubToken: process.env.GITHUB_TOKEN
  - .NET:       GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN")
  - Go:         GitHubToken: os.Getenv("GITHUB_TOKEN")
  - Rust:       opts.github_token = std::env::var("GITHUB_TOKEN").ok()

This is pure boilerplate noise: the runtime CLI already reads GITHUB_TOKEN
from its inherited environment when no token is provided to the SDK, so
the explicit pass-through is redundant and nothing a real consumer would
write. Drop the line in every scenario across all 5 languages.

Exception: `auth/gh-app` keeps explicit github_token plumbing because the
whole point of that scenario is to demonstrate passing an OAuth-derived
token obtained at runtime.

Also clean up the resulting unused imports:

  - Python: `import os` removed where it was only used for GITHUB_TOKEN
    (ruff autofixed).
  - Go: `"os"` import removed where it was only used for GITHUB_TOKEN
    (gofmt happy).
  - Rust: `let mut opts = ClientOptions::default(); ...; Client::start(opts)`
    collapsed to `Client::start(ClientOptions::default())` where opts is
    no longer mutated.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SteveSandersonMS

test/scenarios/auth/byok-anthropic/go/main.go

@@ -59,8 +59,8 @@ func main() {
 	}
 
 	if response != nil {
-if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
-fmt.Println(d.Content)
-}
-}
+		if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
+			fmt.Println(d.Content)
+		}
+	}
 }

test/scenarios/auth/byok-azure/go/main.go

@@ -63,8 +63,8 @@ func main() {
 	}
 
 	if response != nil {
-if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
-fmt.Println(d.Content)
-}
-}
+		if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
+			fmt.Println(d.Content)
+		}
+	}
 }

test/scenarios/auth/byok-ollama/go/main.go

@@ -55,8 +55,8 @@ func main() {
 	}
 
 	if response != nil {
-if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
-fmt.Println(d.Content)
-}
-}
+		if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
+			fmt.Println(d.Content)
+		}
+	}
 }

test/scenarios/auth/byok-openai/go/main.go

@@ -54,8 +54,8 @@ func main() {
 	}
 
 	if response != nil {
-if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
-fmt.Println(d.Content)
-}
-}
+		if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
+			fmt.Println(d.Content)
+		}
+	}
 }

test/scenarios/auth/gh-app/go/main.go

@@ -186,8 +186,8 @@ func main() {
 		log.Fatal(err)
 	}
 	if response != nil {
-if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
-fmt.Println(d.Content)
-}
-}
+		if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
+			fmt.Println(d.Content)
+		}
+	}
 }

test/scenarios/bundling/app-direct-server/go/main.go

@@ -41,8 +41,8 @@ func main() {
 	}
 
 	if response != nil {
-if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
-fmt.Println(d.Content)
-}
-}
+		if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
+			fmt.Println(d.Content)
+		}
+	}
 }

test/scenarios/bundling/container-proxy/go/main.go

@@ -41,8 +41,8 @@ func main() {
 	}
 
 	if response != nil {
-if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
-fmt.Println(d.Content)
-}
-}
+		if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
+			fmt.Println(d.Content)
+		}
+	}
 }

test/scenarios/bundling/fully-bundled/csharp/Program.cs

@@ -3,7 +3,6 @@
 using var client = new CopilotClient(new CopilotClientOptions
 {
     Connection = RuntimeConnection.ForStdio(path: Environment.GetEnvironmentVariable("COPILOT_CLI_PATH")),
-    GitHubToken = Environment.GetEnvironmentVariable("GITHUB_TOKEN"),
 });
 
 await client.StartAsync();

test/scenarios/bundling/fully-bundled/go/main.go

@@ -4,16 +4,13 @@ import (
 	"context"
 	"fmt"
 	"log"
-	"os"
 
 	copilot "github.com/github/copilot-sdk/go"
 )
 
 func main() {
 	// Go SDK auto-reads COPILOT_CLI_PATH from env
-	client := copilot.NewClient(&copilot.ClientOptions{
-		GitHubToken: os.Getenv("GITHUB_TOKEN"),
-	})
+	client := copilot.NewClient(&copilot.ClientOptions{})
 
 	ctx := context.Background()
 	if err := client.Start(ctx); err != nil {
@@ -37,8 +34,8 @@ func main() {
 	}
 
 	if response != nil {
-if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
-fmt.Println(d.Content)
-}
-}
+		if d, ok := response.Data.(*copilot.AssistantMessageData); ok {
+			fmt.Println(d.Content)
+		}
+	}
 }

test/scenarios/bundling/fully-bundled/python/main.py

@@ -1,13 +1,10 @@
 import asyncio
-import os
 
 from copilot import CopilotClient
 
 
 async def main():
-    client = CopilotClient(
-        github_token=os.environ.get("GITHUB_TOKEN"),
-    )
+    client = CopilotClient()
 
     try:
         session = await client.create_session(model="claude-haiku-4.5")