Add MiniMax provider support (#656 by @dannote)

- Add minimax to KnownProvider and Api types
- Add MINIMAX_API_KEY to getEnvApiKey()
- Generate MiniMax-M2 and MiniMax-M2.1 models
- Add context overflow detection pattern
- Add tests to all required test files
- Update README and CHANGELOG with attribution

Also fixes:
- Bedrock duplicate toolResult ID when content has multiple blocks
- Sandbox extension unused parameter lint warning

packages/coding-agent/examples/extensions/sandbox/index.ts

@@ -211,7 +211,7 @@ export default function (pi: ExtensionAPI) {
 	pi.registerTool({
 		...localBash,
 		label: "bash (sandboxed)",
-		async execute(id, params, onUpdate, ctx, signal) {
+		async execute(id, params, onUpdate, _ctx, signal) {
 			if (!sandboxEnabled || !sandboxInitialized) {
 				return localBash.execute(id, params, signal, onUpdate);
 			}