# Watch an Item

## Objective

Follow one record and get told when something changes on it.

Per-record change subscriptions, with automatic watching when a user comments or is assigned, and one-click unwatch.

## Before You Begin

This feature is being added to an application that already exists and already
works. Do not scaffold a new project, and do not assume a blank slate.

Inspect the codebase first and establish:

- The existing application structure and where code of this kind already lives.
- The framework and version in use.
- The existing design system — colours, spacing, typography, and component conventions.
- Existing UI components you can reuse instead of writing new ones.
- The existing database structure, if this feature needs to persist anything.
- The existing authentication and authorization system, if this feature is user-scoped.
- Dependencies already installed, so you don't add a library that duplicates one.
- The existing test setup and conventions.

Only start writing code once you understand the above. If the application
already implements part of this feature, extend it rather than replacing it.

## Implementation Instructions

1. Add a watch subscription joining a user to a single record, with a control on the record itself showing current state and the watcher count.
2. Auto-watch a user when they comment on, are assigned to, or create a record — then tell them you did it, and make the unwatch obvious.
3. Define the exact list of events that notify watchers, and let a watcher mute event types they do not care about while staying subscribed.
4. Put an unwatch action inside every notification the subscription generates, so the user can stop it at the moment it annoys them rather than hunting for the record.
5. Do NOT reuse or duplicate Favorites. Favorites is a personal bookmark for finding things again; a watch is a subscription that sends messages. Keep them as separate state with separate controls.

## UI and UX Requirements

Match the application's existing design system exactly. Reuse its components,
spacing, and typography. This feature should look like it was always there.

## Responsive Requirements

Works on mobile, tablet, and desktop. Touch targets are large enough to hit on a
phone, and nothing overflows horizontally at 320px.

## Accessibility Requirements

- Fully keyboard navigable.
- Correct semantic elements and ARIA roles.
- Visible focus states.
- Meets WCAG AA contrast.
- Dynamic changes are announced to screen readers.
- Respects prefers-reduced-motion.

## Edge Cases

- One user action that fires several internal events must produce one notification, not four.
- A user must never be notified about their own change to a record they watch.
- Losing access to the record must stop delivery immediately, including for anything already queued.
- Deleting, archiving, or merging a record needs a defined outcome for its watchers — silently dropping them loses the notification they were waiting for.
- Watch state belongs to a workspace. The same user in two workspaces must not leak subscriptions between them.
- A record with many watchers must fan out asynchronously; do not send during the request that made the change.

## Testing

Exercise the feature end to end in the running application. Cover every edge case
above, then run the existing test suite and confirm nothing regressed.

## Acceptance Criteria

- [ ] Any record can be watched and unwatched, with the current state visible on the record.
- [ ] Commenting on or being assigned to a record starts a watch and tells the user.
- [ ] Watchers can mute specific event types without unwatching.
- [ ] Every generated notification carries a working unwatch action.
- [ ] Users are not notified about their own changes and duplicate events collapse into one.
- [ ] Revoked access stops delivery immediately, including queued messages.
- [ ] The feature matches the existing design system.
- [ ] No existing functionality is broken.

## Adaptation Rules

- Match the existing design system. Do not introduce a new colour palette,
  spacing scale, or component library.
- Reuse existing components and utilities wherever they fit.
- Follow the naming, file layout, and code style already present.
- Do not upgrade, replace, or remove existing dependencies to make this
  feature fit. Adapt the feature to the app, not the app to the feature.
- Do not break existing functionality. If a change is genuinely required in
  existing code, make the smallest one that works and say so.
- If something in these instructions conflicts with how the application is
  built, follow the application and explain the deviation.

## Final Verification

Before you report the work as done:

1. Re-read the acceptance criteria above and check each one against what you
   actually built.
2. Run the application and exercise the feature end to end.
3. Run the existing test suite and confirm you have broken nothing.
4. Check the feature on mobile, tablet, and desktop widths.
5. Check keyboard navigation and focus handling.
6. Summarize what changed: files added, files modified, and anything you
   deliberately did differently because of how this application is built.

If any acceptance criterion is unmet, fix it before reporting completion.