fix(provider): enforce chunk timeout regardless of content type

[totalolage]

Issue for this PR

Upstream PR: anomalyco#47621
Upstream issue: anomalyco#47605

Type of change

• Bug fix

What does this PR do?

Bring the upstream timeout fix into our fork so we can use it before upstream merges it.

chunkTimeout currently only checks responses marked text/event-stream. If a provider omits or mislabels that header, a stalled response can leave the session waiting indefinitely.

Remove the header check so the existing timeout covers all response bodies through the SDK fetch wrapper, including Bedrock binary streams and JSON. Timeout defaults and opt-outs are unchanged. Native and WebSocket transports are outside this change.

This is the same reviewed commit as the upstream PR: e22295a175b74090549115e0eb02b64af6aefb3e. It merges cleanly with the fork’s CI and self-update changes.

How did you verify your code works?

• 139 focused tests passed on the fix commit.
• bun typecheck passed in packages/opencode.
• Full package suite: 3559 passed, 26 failed, 22 skipped, one todo. All 26 failures also reproduced against the original implementation in the same environment.
• Independent code review approved the patch.

The full run used a worktree-local TMPDIR after /tmp filled, which affected unrelated tests. A clean-environment full-suite pass remains unverified. These test results are for the fix commit before merging with the fork’s additional changes; fork CI must check the combined result.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

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