Codex/qq local file upload

[xiang33]

📝 Description

This PR improves QQ channel support for local file attachments.

Previously, the QQ channel could only send media when the attachment reference was already an http/https URL. Locally generated files such as PDF, HTML, and other attachments could not be sent correctly through QQ. In addition, even after adding local upload support, uploaded files could appear as unnamed attachments because the filename was not forwarded to the QQ upload request.

This PR updates the QQ channel to:

• upload local attachments before sending QQ rich media messages
• return explicit errors when upload or send fails, instead of silently pretending success
• preserve attachment filenames during local upload, so files such as conversation.pdf are displayed with the expected name on the receiving side

🗣️ Type of Change

• 🐞 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 📖 Documentation update
• ⚡ Code refactoring (no functional changes, no api changes)

🤖 AI Code Generation

• 🤖 Fully AI-generated (100% AI, 0% Human)
• 🛠️ Mostly AI-generated (AI draft, Human verified/modified)
• 👨‍💻 Mostly Human-written (Human lead, AI assisted or none)

🔗 Related Issue

N/A

📚 Technical Context (Skip for Docs)

• Reference URL: QQ Bot rich media / file upload API behavior

• Reasoning:
  The previous QQ implementation only supported direct rich media sending when the attachment reference was already a remote URL. Local files resolved from the media store could not be delivered correctly.

  This PR updates the QQ channel to:

  1. resolve local media references from the media store
  2. upload the local file to QQ first
  3. send the uploaded file as a QQ rich media message
  4. return explicit errors when upload or send fails
  5. preserve the original attachment filename in the QQ upload payload

  This keeps the existing direct-send behavior for remote http/https URLs, while adding support for locally generated files such as PDF and other attachments.

🧪 Test Environment

• Hardware: PC (Apple Silicon)
• OS: macOS
• Model/Provider: N/A
• Channels: QQ

📸 Evidence (Optional)

Click to view Logs/Screenshots

go test ./pkg/channels/qq -v -count=1

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[yinwm]

@xiang33 plz sign CLA

[xiang33]

@xiang33 plz sign CLA

done

[xiang33]

fixed lint error, plz rerun the ci

[yinwm]

@xiang33 still should sign CLA, you'd better check your email which sign CLA should in you github email list

[yinwm]

🔔 PR #1722 has been merged

QQ local file upload support has been implemented in #1722 which was just merged to main.

What's already covered:

• Local file → base64 upload via /files API
• max_base64_file_size_mib config option
• Inbound attachment download and storage
• Two-step upload flow (upload → send with file_info)
• Comprehensive test coverage

Potential follow-ups:

If you'd like to contribute additional features, can rebase onto latest main and focus on:

• File name preservation (your PR's focus)
• File caching to avoid duplicate uploads (feat(qq): qq channel supports directly pushing local multimedia files, such as images and files #1227 has this)
• Retry mechanism with exponential backoff

Would you like to close this PR or rebase and contribute the file name preservation feature?