aisman

Direct session 1, Step 4: Bug fixes — diff, save, filter, folder, project CRUD and comparison redesign

Issues implemented:
- Fix ds_* session number showing #-1 instead of absolute value
- Re-check aisman reference after file is saved, not just after adding reference
- Save button should be disabled by default until content differs from disk
- Save instructions should not show file picker dialog every time
- Fix comparison showing all lines as changed when content is identical
- Redesign comparison to 2-column checkbox-based UI
- Fix jQuery error when filtering projects with dot in name
- Show full folder path not just folder name in all folder picker locations
- Fix new project dialog closing prematurely or looping
- Add project delete with double confirmation
- Show folder access granted status under ROOT FOLDER heading
- Add remove folder access permissions button
- Prevent duplicate project names
- Add HttpDelete endpoint for projects