This is still WIP, mostly pending styling. I added a pretty rudimentary
text field and no buttons whatsoever other than that. I am targeting a
Preview of 09.13, as I am gonna be on PTO for the next week.
I dislike the current implementation slightly because of `regex`'s crate
syntax and lack of support of backreferences. What strikes me as odd wrt
to syntax is that it will just replace a capture name with empty string
if that capture is missing from the regex. While this is perfectly fine
behaviour for conditionally-matched capture groups (e.g. `(foo)?`), I
think it should still error out if there's no group with a given name
(conditional or not).
Release Notes:
- Added "Replace" functionality to buffer search.
The major change here is a refactoring to allow controling the save
behaviour when closing items, which is pre-work needed for vim command
palette.
For zed-industries/community#1868
### Summary
This PR introduces channels: a new way of starting collaboration
sessions. You can create channels and invite others to join them. You
can then hold a call in a channel, where any member of the channel is
free to join the call without needing to be invited.
Channels are displayed in a new panel called the collaboration panel,
which now also contains the contacts list, and the current call. The
collaboration popover has been removed from the titlebar.

For now, the channels functionality will only be revealed to staff, so
the public-facing change is just the move from the popover to the panel.
### To-do
* User-facing UI
* [x] signed-out state for collab panel
* [x] new icon for collab panel
* [x] for now, channels section only appears for zed staff
* [x] current call section styling
(https://zed-industries.slack.com/archives/C05CJUNF2BU/p1691189389988239?thread_ts=1691189120.403009&cid=C05CJUNF2BU)
* [x] Channel members
* Channels
* [x] style channel name editor
* [x] decide on a special "empty state" for the panel, when user has no
contacts
* [x] ensure channels are sorted in a consistent way (expose channel id
paths to client)
* [x] Figure out layered panels UX
* [x] Change add contacts to be the same kind of tabbed modal
* [x] race condition between channel updates and user fetches
(`ChannelStore::handle_update_contacts`)
* [x] race condition between joining channels and channel update
messages `collab::rpc::channel_updated`)
* [x] don't display mic as muted when microphone share is pending upon
first joining call
Release Notes:
- Moved the collaboration dropdown into its own panel.
- Added settings for disabling the AI assistant panel button.
- Switch to lazily initializing audio output sources
(https://github.com/zed-industries/community/issues/1840,
https://github.com/zed-industries/community/issues/1919)
I want to use this on another branch, but it's a sweeping change,
so this prepares the ground for it. This can always be reverted if
it doesn't work out.