adds one-tap +1 acknowledgement to supported unread issue and pull conversations
resolves repository and latest comment only from the authenticated notification thread
reconciles an existing operator reaction before marking read, making partial-failure retries safe
advances through the existing mobile unread-update reader only after server confirmation
keeps the control unavailable for unsupported and cached/offline updates
Verification
focused behavior tests: 20 passed
full suite: 1112 passed
rendered at 390x844 and 320x568: 44px control, no horizontal overflow
Closes #539
## Outcome
- adds one-tap +1 acknowledgement to supported unread issue and pull conversations
- resolves repository and latest comment only from the authenticated notification thread
- reconciles an existing operator reaction before marking read, making partial-failure retries safe
- advances through the existing mobile unread-update reader only after server confirmation
- keeps the control unavailable for unsupported and cached/offline updates
## Verification
- focused behavior tests: 20 passed
- full suite: 1112 passed
- rendered at 390x844 and 320x568: 44px control, no horizontal overflow
Blocking a user prevents them from interacting with repositories, such as opening or commenting on pull requests or issues. Learn more about blocking a user.
Closes #539
Outcome
Verification