Add and manage subject keywords during item submission in DSpace 7

[cyphun]

As a user submitting a new item in DSpace,
I want to add subject keywords by selecting from existing keywords or creating new ones,
so that I can accurately describe the item’s content and ensure the keywords are updated in the database.

Acceptance Criteria:

• Adding Existing Keywords:
  • The user can search for and select multiple keywords from a list of existing subject keywords.
  • Selected keywords appear as tags or chips, which can be removed if necessary.
• Adding New Keywords:
  • The user can free-type new keywords in a text input field.
  • Free-typed keywords are immediately added as tags or chips and saved to the keyword database upon submission.
• Keyword Database Update:
  • Any new keywords entered by the user are stored in the keyword database and become available for future use by others.
• Unlimited Keywords:
  • The user can add as many existing or new keywords as needed without restrictions on the number of keywords.
• Validation and Submission:
  • All selected and entered keywords are included in the item metadata upon successful submission.

Additional Notes:

• UI Considerations:
  • The interface should provide autocomplete suggestions for existing keywords as the user types.
  • New keywords should be visually distinct (e.g., styled differently) until submission is complete.

[cyphun]

@mfgaede Found this that I think is related to this issue: DSpace/dspace-angular#2435

@john-zhang1 thanks for taking a look

[cyphun]

@caflynn This is ready to be reviewed at: https://dev.scholarsbank.uoregon.edu/

[cyphun]

@caflynn When this looks good, we can get this moved into production, so just let us know.