V4.15.5

📦 Upgrade Guide

Image Changes

• Update the fastgpt-app (FastGPT core service) image tag to v4.15.5.
• Update the fastgpt-pro (FastGPT commercial edition) image tag to v4.15.5.
• Update the fastgpt-plugin image tag to v1.0.3.

🚀 New Features

1. Added Cloudflare R2 object storage support, including the R2 S3 API, presigned access, and custom domains for public buckets.
2. Added the SoMark PDF enhanced parsing provider. Configure it with SOMARK_API_KEY; when multiple PDF providers are configured, FastGPT uses this priority order: custom PDF parsing service, SoMark, TextIn, then Doc2x. See the environment variable configuration for details.

⚙️ Improvements

1. Centralized more workspace dependency versions in the pnpm catalog and refreshed the lockfile.
2. Added Chinese and English runtime fonts to the Agent Sandbox image to improve font availability for text and image-related tasks.
3. Updated the OSS adapter to support string uploads required by the IStorage contract and to preserve the stored Content-Type when OSS does not support response-header overrides.
4. Added a missing-object preflight to the COS adapter so downloads follow the shared error contract.

🐛 Fixes

1. Fixed Alibaba Cloud OSS metadata reads that looked for ETags in the wrong response field, causing missing ETags and downstream metadata validation failures.
2. Fixed missing S3/MinIO source files being surfaced as Unknown; they now return a translated file-not-found error with HTTP 404.
3. Fixed input fields disappearing from older plugin nodes after an upgrade.
4. Fixed avatar URLs being encoded twice.

🛠️ Code Improvements

1. Added cross-provider S3 SDK integration tests for MinIO, AWS S3, Cloudflare R2, Alibaba Cloud OSS, and Tencent Cloud COS, covering private/public buckets, public URLs, and real presigned URL access.