Add bulk operations to hosted instance list pages

Remote instance pages support selecting multiple items and performing bulk operations on them. Hosted instance pages don't have this at all, neither at the team level nor the application level.

## Current state

* **Team remote instances**: Full bulk operations (move to instance, move to application, remove from instance/application, assign/unassign group, delete)
* **Application remote instances**: Same bulk operations scoped to the application context
* **Team hosted instances** (`pages/team/Instances.vue`): No bulk operations, no row checkboxes, no bulk action menu
* **Application hosted instances** (`pages/application/Overview.vue`): No bulk operations, no row checkboxes, no bulk action menu. Only per-row context menu actions (start, restart, suspend, delete).

## What needs to happen

* Add bulk operation support to both team and application hosted instance pages
* The general rule: any operation you can perform on a single hosted instance should be available as a bulk operation, unless it only makes sense for a single instance. Sensible bulk operations:
* Start
* Restart
* Suspend
* Delete
* Update (stack/type updates)
* Operations that should **not** be bulk:
* Download/export snapshots (scoped to individual instances)
* Rollback to snapshot (requires choosing a specific snapshot per instance)
* Will likely need new backend endpoints for bulk hosted instance operations, similar to the existing `DELETE /api/v1/teams/:teamId/devices/bulk` and `PUT /api/v1/teams/:teamId/devices/bulk` pattern

Depends on #8114.