fix(sdk/python): forward MiniMax v1 video optional fields regressed by #854

[AbirAbbas]

Summary

PR #854 (MiniMax H3 video v2) promoted content, ratio, callback_url, and aigc_watermark from **kwargs to named parameters on MiniMaxProvider.generate_video, then added a guard rejecting all four for any non-H3 model. In v0.1.123 the last three fell through **kwargs → overrides → the v1 /video_generation request body and were forwarded verbatim (callback_url and aigc_watermark are documented v1 fields), so existing Hailuo callers like

await provider.generate_video(prompt, model="minimax/MiniMax-Hailuo-02", duration=6, callback_url="https://hook.example/cb")

now raise ValueError("MiniMax v2 request fields require the MiniMax-H3 model") instead of submitting the job.

Changes Made

• Forward ratio, callback_url, and aigc_watermark verbatim into the v1 request body when provided, restoring v0.1.123 behavior byte-for-byte.
• Keep the client-side guard for content only: structured content is a v2 request shape that never worked against v1, so the clear error is strictly better than the old server-side rejection.
• No new names in the reserved override check, so the extra={"callback_url": ...} path (which kept working throughout) is unchanged.

Validation Contract

1. A v1 (non-H3) call passing ratio / callback_url / aigc_watermark as named kwargs submits them verbatim in the v1 POST body with no exception — covered by test_minimax_video_legacy_forwards_v1_optional_fields.
2. content=[...] with a non-H3 model still raises a clear ValueError — covered by test_minimax_video_legacy_rejects_h3_structured_content.
3. H3 path behavior is untouched (existing H3 tests unchanged and passing).

Test Plan

• Differential probe against a v0.1.123 checkout (captured submit bodies): all five scenarios — each named field, plain control, and the extra= path — are byte-identical between v0.1.123 and this branch.
• ruff check . clean at CI's pinned 0.15.22; ruff format --check clean on touched files.
• Full sdk/python suite: 1872 passed, 4 skipped (includes the 2 new tests).

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🤖 Generated with Claude Code

[github-actions]

Performance

SDK	Memory	Δ	Latency	Δ	Tests	Status
Python	9.0 KB	-	0.38 µs	+9%	✓	✓

✓ No regressions detected

[github-actions]

📊 Coverage gate

Thresholds from .coverage-gate.toml: per-surface ≥ 84%, aggregate ≥ 85%, max per-surface regression ≤ 1.0 pp, max aggregate regression ≤ 0.50 pp.

Surface	Current	Baseline	Δ
control-plane	87.10%	87.40%	↓ -0.30 pp	🟡
sdk-go	92.70%	92.00%	↑ +0.70 pp	🟢
sdk-python	93.82%	93.73%	↑ +0.09 pp	🟢
sdk-typescript	91.17%	90.42%	↑ +0.75 pp	🟢
web-ui	84.75%	84.79%	↓ -0.04 pp	🟡
aggregate	85.62%	85.75%	↓ -0.13 pp	🟡

✅ Gate passed

No surface regressed past the allowed threshold and the aggregate stayed above the floor.

[github-actions]

📐 Patch coverage gate

Threshold: 80% on lines this PR touches vs origin/main (from .coverage-gate.toml:thresholds.min_patch).

Surface	Touched lines	Patch coverage	Status
control-plane	0	—	➖ no changes
sdk-go	0	—	➖ no changes
sdk-python	0	—	➖ no changes
sdk-typescript	0	—	➖ no changes
web-ui	0	—	➖ no changes

✅ Patch gate passed

Every surface whose lines were touched by this PR has patch coverage at or above the threshold.