feat(plugins): 方舟 Agent Plan - 新增图片与视频协议插件

独立 /api/plan/v3 Seedream、Seedance 插件，并同步宿主能力默认值与渠道识别，避免与官方 /api/v3 凭证混用。

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/components/video-settings-panel.tsx

@@ -3,6 +3,7 @@ import { Switch } from "@/components/ui/base/switch";
 
 import { ImageSettingsTheme } from "@/components/image-settings-panel";
 import { boolConfig, isSeedanceFastModel, isSeedanceVideoConfig, normalizeSeedanceDuration, normalizeSeedanceRatio, normalizeSeedanceResolution, seedanceRatioOptions } from "@/lib/seedance-video";
+import { isVolcengineArkVideoProtocol } from "@/lib/model-protocols";
 import { type CanvasTheme } from "@/lib/canvas-theme";
 import { formatVideoResolutionLabel, isVideoResolutionMatch, normalizeVideoDuration, videoDimensionsForRatioAndResolution, videoResolutionComparisonKey, VIDEO_DURATION_MIN } from "@/lib/video-generation-options";
 import { modelCapabilityConfigFor, resolveVideoRatioValue, resolveVideoResolutionValue, videoDurationOptions, type VideoCapabilityConfig } from "@/lib/model-capabilities";
@@ -115,7 +116,7 @@ function SeedanceVideoSettingsPanel({ config, profile, priceTiers, onConfigChang
     const generateAudio = boolConfig(config.videoGenerateAudio, profile.generateAudio.default);
     const watermark = boolConfig(config.videoWatermark, profile.watermark.default);
     const useArkPrivateAssets = boolConfig(config.videoArkPrivateAssetUpload, true);
-    const isArkSeedance = resolveModelRequestConfig(config, config.model).interfaceType === "volcengine-ark-video";
+    const isArkSeedance = isVolcengineArkVideoProtocol(resolveModelRequestConfig(config, config.model).interfaceType);
 
     return (
         <ImageSettingsTheme theme={theme}>