fix(opencode): retry raw network finish errors (#43813)

Co-authored-by: Aiden <rekram1-node@users.noreply.github.com>

packages/opencode/test/session/llm.test.ts

@@ -27,6 +27,7 @@ import { ModelV2 } from "@opencode-ai/core/model"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/core/effect/layer-node"
 import { LayerNodePlatform } from "@opencode-ai/core/effect/app-node-platform"
+import { ProviderError } from "@/provider/error"
 
 type ConfigModel = NonNullable<NonNullable<ConfigV1.Info["provider"]>[string]["models"]>[string]
 
@@ -832,6 +833,70 @@ describe("session.llm.stream", () => {
     },
   )
 
+  it.instance(
+    "surfaces network_error finish reasons as retryable stream failures",
+    () =>
+      Effect.gen(function* () {
+        const fixture = loadFixture(vivgridFixture.providerID, vivgridFixture.modelID)
+        const request = waitRequest(
+          "/chat/completions",
+          createEventResponse(
+            [
+              {
+                id: "chatcmpl-network-error",
+                object: "chat.completion.chunk",
+                choices: [{ index: 0, delta: { role: "assistant", content: "" }, finish_reason: "network_error" }],
+              },
+            ],
+            true,
+          ),
+        )
+        const resolved = yield* Provider.use.getModel(
+          ProviderV2.ID.make(vivgridFixture.providerID),
+          ModelV2.ID.make(fixture.model.id),
+        )
+        const sessionID = SessionID.make("session-test-network-error")
+        const agent = {
+          name: "test",
+          mode: "primary",
+          options: {},
+          permission: [{ permission: "*", pattern: "*", action: "allow" }],
+        } satisfies Agent.Info
+        const user = {
+          id: MessageID.make("msg_user-network-error"),
+          sessionID,
+          role: "user",
+          time: { created: Date.now() },
+          agent: agent.name,
+          model: { providerID: ProviderV2.ID.make(vivgridFixture.providerID), modelID: resolved.id },
+        } satisfies SessionV1.User
+
+        const error = yield* drain({
+          user,
+          sessionID,
+          model: resolved,
+          agent,
+          system: ["You are a helpful assistant."],
+          messages: [{ role: "user", content: "Hello" }],
+          tools: {},
+        }).pipe(Effect.flip)
+        yield* Effect.promise(() => request)
+
+        if (!(error instanceof ProviderError.ResponseStreamError)) throw error
+        expect(error.message).toBe("Provider finish_reason: network_error")
+      }),
+    {
+      config: () => ({
+        enabled_providers: [vivgridFixture.providerID],
+        provider: {
+          [vivgridFixture.providerID]: {
+            options: { apiKey: "test-key", baseURL: `${state.server!.url.origin}/v1` },
+          },
+        },
+      }),
+    },
+  )
+
   const cerebrasFixture = { providerID: "cerebras", modelID: "gpt-oss-120b" }
   it.instance(
     "replays Cerebras assistant reasoning using the provider-supported field",