Update username regex pattern in routes

[KipSigei]

Changes / Features implemented

• Updates the regex pattern to accommodate usernames with a broader range of characters. While the previous pattern (?P<username>\w+) only allowed alphanumeric characters and underscores, the new pattern (?P<username>[^/]+) permits any characters except forward slashes

Steps taken to verify this change does what is intended

• Added tests

Side effects of implementing this change

• The change permits any username characters except forward slashes

Before submitting this PR for review, please make sure you have:

• Included tests
• Updated documentation

Closes #