Lz/dev

[DeepThinkingZhouLiu]

Summary

This PR merges the recent lz/dev capability upgrades into the target branch, including new
paper-derived generation workflows, frontend entry pages, backend adapters/services, and
deployment/runtime improvements.

2. Add Paper2Poster end-to-end capability

• Added postertool toolkit and poster generation pipeline
• Added backend service/router/schema support
• Added frontend upload/generate/complete flow and related locale resources
• Added poster worker and CLI scripts

3. Upgrade Paper2Video workflow and product flow

• Added/updated Paper2Video workflow, subprocess support, API service, router, adapter, and UI
  flow
• Added avatar/audio/example assets and related worker/CLI scripts
• Added EchoMimic-related support scripts/configs
• Improved script/subtitle/cursor-related agent flow

4. Improve PPT and long-document related workflows

• Updated PPT-related toolkits/services/adapters/CLI scripts
• Adjusted long-paper parsing/support utilities, including markdown-section handling
• Updated paper2ppt, pdf2ppt, and ppt2polish related frontend/backend wiring
• Included several bug fixes around PPT generation flow

5. Deployment and runtime improvements

• Improved deploy/start.sh, deploy/stop.sh, and deploy/restart.sh
• Updated model-server startup flow and SAM3-related import/runtime handling
• Added sam3_import_helper.py
• Removed obsolete scripts such as script/start_model_servers.py
• Updated .env.example, docs, and some startup/backend glue code

6. Cleanup and repo organization

• Moved a number of ad hoc tests into tests/manual/...
• Removed some obsolete tests/utilities
• Updated README / README_CN and related config references

Impact

This PR touches:

• backend workflows/services/routers/schemas
• frontend pages/sidebar/i18n/API wiring
• model/deployment scripts
• new static assets and worker scripts

Notes / Risk

This is a relatively large feature + integration PR. Suggested regression focus:

• Paper2Citation generation path
• Paper2Poster generation path
• Paper2Video full flow
• Paper2PPT / PDF2PPT / PPT Polish existing flows
• model service startup, especially SAM3-related configuration
• frontend route/sidebar visibility and API connectivity

Testing

Not fully regression-tested in this PR description.
Recommended manual verification on the main user flows above before merge.