fix AI-162
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **Chores**
- Improved database migration scripts to prevent errors by ensuring changes are only applied if relevant tables exist. No visible changes to user features or functionality.
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fix AI-131
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **Refactor**
- Updated database schema to consolidate unique constraints into composite primary keys for embedding-related data, improving consistency.
- Changed the relation in the Snapshot model to allow multiple embeddings.
- Improved filtering logic for documents and snapshots based on embedding existence.
- Reformatted SQL queries and schema attributes for improved readability; no changes to functionality.
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close CLOUD-207
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Introduced automated periodic indexing of workspaces with a new job type and a scheduled cron job running every 30 seconds.
- Added a unique sequential identifier (`sid`) and an "indexed" flag to workspaces to track indexing status.
- **Improvements**
- Enhanced workspace indexing to handle missing workspaces and snapshots distinctly and selectively index documents.
- Added ability to query workspaces after a given identifier with result limits.
- **Bug Fixes**
- Improved error handling and logging during workspace indexing operations.
- **Tests**
- Expanded test coverage for workspace indexing and auto-indexing, including scheduling and edge cases.
- **Chores**
- Updated data models and schema to support new workspace fields and indexing features.
- Enhanced mock data utilities to allow custom timestamps.
- Improved type safety and flexibility in document snapshot retrieval.
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fix AI-20
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Enhanced file metadata with MIME type, blob ID, and file name across context and workspace, now visible in UI and API.
- Added workspace-level matching for files and documents with configurable thresholds and workspace scoping in search queries.
- Introduced a new error type and user-friendly messaging for global workspace context matching failures.
- **Bug Fixes**
- Improved consistent handling of file MIME types and nullable context IDs for accurate metadata.
- **Documentation**
- Updated GraphQL schema, queries, and mutations to include new metadata fields, optional parameters, and error types.
- **Style**
- Added new localization strings for global context matching error messages.
- **Tests**
- Extended test coverage with new and updated snapshot tests for metadata and matching logic.
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Close [AI-116](https://linear.app/affine-design/issue/AI-116)
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Added support for specifying alternative AI models in chat prompts, enabling users to select from multiple available models.
- Expanded AI model options with new additions: 'gpt-4.1', 'o3', and 'claude-3-5-sonnet-20241022'.
- **Enhancements**
- Users can now optionally choose a specific AI model during chat interactions.
- Prompts and chat sessions reflect and support selection of alternative models where applicable.
- **Bug Fixes**
- Improved handling of prompt configuration defaults for better reliability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Added support for installing self-hosted team licenses via encrypted license files.
- Introduced a new "Onetime" license variant for self-hosted environments.
- Added a GraphQL mutation to upload and install license files.
- License details now display the license variant.
- **Bug Fixes**
- Improved error messages for license activation and expiration, including dynamic reasons.
- **Localization**
- Updated and improved license-related error messages for better clarity.
- **Tests**
- Added comprehensive end-to-end tests for license installation scenarios.
- **Chores**
- Enhanced environment variable handling and public key management for license verification.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
