Epic: private local PDF assistant #80

Build an optional assistant that can understand and act on PDFs without sending document content off-device.

Implementation is tracked through the GitHub sub-issues attached to this epic. Foundation work lands first, followed by document understanding, safe action planning, and the editor prototype.

Product rules

• Existing non-AI tools remain complete and usable without a model.
• No account, cloud API, background upload, or silent remote fallback.
• Models are never downloaded without an explicit choice.
• Document actions always show a concrete preview and require confirmation.
• AI-assisted editing stays within operations OffPDF can verify and undo.
• Unrestricted rewriting of arbitrary existing PDF text is not promised.

This epic is complete when the local runtime is optional and removable, document answers are page-grounded, proposed actions are schema-validated, and supported edits remain reviewable before export.