Implement proofread filter functionality to Browse Chants page

[lucasmarchd01]

This PR introduces functionality for filtering by proofreading status on the "Browse Chants" page. It includes:

• Filtering functionality for manuscript_full_text_proofread, manuscript_full_text_std_proofread, and volpiano_proofread fields.
• JavaScript updates to update URL parameters dynamically as the user selects different proofreading options.
• Forms with ChoiceField and RadioSelect widgets for filtering chants based on proofreading status.
• User permission checks to determine if a user can proofread a specific source.
• Templates are updated to reflect the new proofreading filter options.
• Add a test suite for these changes

Updated screenshot:

Towards #1492

[lucasmarchd01]

Just adding another thought here...
I implemented this on the Source Browse Chants page. However, it could be on the source inventory page instead (or both). My thought was that since the browse chants page also has the "Edit" links it would be easier for a proofreader to filter and edit these chants directly. But if this looks to cluttered or belongs on another page we can definitely switch that before merging.

[dchiller]

What's here look good, but I think it would be to not close #1492 yet, because what's here is useful for seeing what chants in a source need proofreading, but you have to know which sources have these chants to make it useful. I'm not sure if that's always the case? Maybe @annamorphism can let us know based on experience. If it's helpful to see this at the source level too, we may want to add a similar function to the Source List page.

[annamorphism]

What's here look good, but I think it would be to not close #1492 yet, because what's here is useful for seeing what chants in a source need proofreading, but you have to know which sources have these chants to make it useful. I'm not sure if that's always the case? Maybe @annamorphism can let us know based on experience. If it's helpful to see this at the source level too, we may want to add a similar function to the Source List page.

@dchiller yes, it's not always known at the source level if a source is "done" or not--for example, I know I've proofread some fragments from Trier and not others. This way I can go in and check, but a little flag that "this source has some chants that need proofreading" would help find them.