This PR makes the channel buttons square.

Release Notes:

- Adjusted the shape of the channel buttons.

This PR adds the `color` crate, which will be the home of a number of
color-related utilities, and also acts as an interface between
[`palette`](https://crates.io/crates/palette) and the way `gpui` colors
work.

The goal of this crate is to centralize color utilities like mixing and
blending, building color ramps and sets of colors for state and more.

## Todo:

- [x] hex -> Color
- [x] Color mixing
- [x] Color blending using blend modes (overlay, multiply, etc)
- [ ] ~~Build color ramp from color~~
- [x] Build state set from color
- [ ] ~~Update Theme to use the color crate~~

Release Notes:

- None (Internal changes: Adds the `color` crate for working with
colors.)

In #3910 we made the welcome screen use the same background color as the
editor.

However, this later regressed in
cdd5cb16ed896b2ee3bbb041983ee7cb812f6991.

This PR fixes that regression and restores the correct color for the
welcome page.

Release Notes:

- Fixed the background color of the welcome screen.

Release Notes:

- Improves the rendering of the facepile in the titlebar with many
people

Release Notes:

- Fixes a bug where you could not use call controls after a project was
unshared

Release Notes:

- Fixed a bug allowing certain UI elements to render incorrectly when
overlapping.

This removes the terminal performance slightly by removing memmoves that
aren't needed after inlining a call.

It also removes a possibly unnecessary `String` allocation.

Release Notes:

- Improved terminal rendering performance by reducing allocations and
memory operations.

Co-authored-by: Antonio <antonio@zed.dev>

Before this change we wouldn't submit all possible primitives of the
same kind that are less-than the max order.

Result was that we would submit, say, 10 paths each in a separate batch
instead of actually batching them.

This was overly strict because even if the order of two different
primitives was the same, we could have still batched the 1st primitive
kind, if its implicit ordering was less than 2nd kind.

Example: say we have the following primitives and these orders

  5x paths, order 3
  2x sprites, order 3

Previously, we would submit 1 path, 1 path, 1 path, 1 path, 1 path, then
the sprites.

With this changes, we batch the 5 paths into one batch.

Release Notes:

- Improved performance when rendering lots of selection.

Before this change we wouldn't submit all possible primitives of the
same kind that are less-than the max order.

Result was that we would submit, say, 10 paths each in a separate batch
instead of actually batching them.

This was overly strict because even if the order of two different
primitives was the same, we could have still batched the 1st primitive
kind, if its implicit ordering was less than 2nd kind.

Example: say we have the following primitives and these orders

  5x paths, order 3
  2x sprites, order 3

Previously, we would submit 1 path, 1 path, 1 path, 1 path, 1 path, then
the sprites.

With this changes, we batch the 5 paths into one batch.

Co-authored-by: Antonio <antonio@zed.dev>

This "adds" the keybindings I was missing in Vim mode (e.g. `Ctrl-[` to
cancel a selection) by fixing the definitions in the keymap from
`Ctrl+[` to `Ctrl-[`.

Release Notes:

- Fixed missing `Ctrl-[` keybindings in Vim mode where `Ctrl-[` should
act like `Esc` but didn't.

This "adds" the keybindings I was missing in Vim mode (e.g. `Ctrl-[` to
cancel a selection) by fixing the definitions in the keymap from
`Ctrl+[` to `Ctrl-[`.

Previously, we were using `size_of` but passing the wrong type in
(`MonochromeSprite` instead of `PathSprite`). This caused us to read
outside of the `sprites` smallvec and triggered the segfault. This
reverts #4078 because I don't think using a `SmallVec` was the issue (it
might have masked this problem though, because we would most of the time
copy from the stack and not from the heap).

With this pull request we are also fixing another potential source of
segfaults, due to checking if we exhausted the instance buffer too late
when drawing underlines.

Release Notes:

- Fixed a crash that could happen during rendering.

Attempts to fix 
<img width="472" alt="Screenshot 2024-01-16 at 19 41 56"
src="https://github.com/zed-industries/zed/assets/2690773/5a8d0691-eabb-4e92-9186-362ca8ef9ca6">

by switching from buttons to labels (so that they can wrap) and adding a
background to them, so they are more visible

<img width="446" alt="image"
src="https://github.com/zed-industries/zed/assets/2690773/bb228aae-0abc-45b4-a0f5-a928a2e64390">
<img width="485" alt="image"
src="https://github.com/zed-industries/zed/assets/2690773/b7fa3598-59b8-4a74-97e6-790695e37047">


Release Notes:

- N/A

This fixes another potential segfault.

Previously, we were using `size_of` but passing the wrong type in
(MonochromeSprite instead of PathSprite). This caused us to read outside
of the `sprites` smallvec and triggered the segfault.

This PR tweaks the positioning of the mute indicators so that they cover
a little bit less of the avatar:

#### Before

<img width="305" alt="Screenshot 2024-01-16 at 6 32 51 PM"
src="https://github.com/zed-industries/zed/assets/1486634/3f6ad2f4-2c3e-498b-97a4-8b522f3ceda9">

#### After

<img width="311" alt="Screenshot 2024-01-16 at 6 26 48 PM"
src="https://github.com/zed-industries/zed/assets/1486634/37161557-084d-4b69-b61f-a0958e8e867c">

(It's a bit hard to tell in the screenshot, but there is a gap between
the bottom of the indicator and the top of the color ribbon).

Release Notes:

- N/A

Always attempt to flush after the timeout period.

Release Notes:

- N/A

We're occasionally seeing a crash in MetalRenderer::draw.

Looking at the backtrace, it seems almost certainly to be happening in
the call to `ptr::copy_nonoverlapping` on line 604 (see `#Don't Panic!`
channel notes)

As we already have added bounds checking to the destination, it seems
most
likely (however improbable) that somehow we're getting an invalid Ptr
and
length from the SmallVec.

To try and make progress on this, let's try a Vec for a bit lest there
is a subtle issue in SmallVec (though I couldn't spot one).


Release Notes:

- (maybe) Fixes SEGFAULT in MetalRenderer::draw

This PR increases the width of the border that we use to indicate when a
call participant is speaking.

This should make it more apparent in the UI when someone is speaking.

Release Notes:

- Increased the width of the ring used to indicate when someone is
speaking in a call.

[[PR Description]]

Release Notes:

- Adds Channels, a new mechanism for collaboration. [Read
More...](https://zed.dev/blog/channels)

- Close modals when focus leaves
- Disallow self-management for admins

Release Notes:

- Fixes changing role of invited channel members

This PR improves the muted indicators to make it clearer when a call
participant is muted.

Previously we used a red border color to denote when a participant was
muted.

Now we render an indicator with an icon to more clearly indicate the
participant's muted status:

<img width="303" alt="Screenshot 2024-01-16 at 4 05 15 PM"
src="https://github.com/zed-industries/zed/assets/1486634/d30fcd84-48e7-4959-b3c4-1054162c6bd6">

Hovering over the indicator will display a tooltip for further
explanation:

<img width="456" alt="Screenshot 2024-01-16 at 4 05 25 PM"
src="https://github.com/zed-industries/zed/assets/1486634/6345846f-196c-47d9-8d65-c8d86e63f823">

This change also paves the way for denoting the deafened status for call
participants.

Release Notes:

- Improved the mute indicator for call participants.

This PR adds a color ribbon for the local player in the current call.

This fixes the alignment of the local user's avatar so that it lines up
with the rest of the collaborators in the call:

<img width="307" alt="Screenshot 2024-01-16 at 2 56 04 PM"
src="https://github.com/zed-industries/zed/assets/1486634/979ee3fa-70c9-482a-9351-020402ad68b9">

Release Notes:

- Added a color ribbon for the local player when in a call.

This PR reworks the way we add indicators to `Avatar`s to make them more
general-purpose.

Previously we had logic specific to the availability indicator embedded
in the `Avatar` component, which made it unwieldy to repurpose for
something else.

Now the `indicator` is just a slot that we can put anything into.

Release Notes:

- N/A

This adjusts the solution in
https://github.com/zed-industries/zed/pull/4014 to fix the double-focus
issue, allowing each pane's project search to work independently.

Release Notes:

- Changed the name of the `workspace::DeploySearch` action to
`pane::DeploySearch` and changed it's behavior to open a new search OR
focus an existing project search in the current pane.
(https://github.com/zed-industries/community/issues/2395)

This fixes block headers overlapping over text in the buffer when using
a custom line height of 1.25.

It fixes the issue by making the parent container a v-flex,
vertically-justifying the content and moving from relative padding to
absolute padding for the header itself.

## Before/After

With setting:
```json
  "buffer_line_height": {
    "custom": 1.25
  },
```

### Before

![screenshot-2024-01-16-16 48
48@2x](https://github.com/zed-industries/zed/assets/1185253/8c3b977e-333f-403c-a4d3-0911f3fac5e0)

### After

![screenshot-2024-01-16-16 50
13@2x](https://github.com/zed-industries/zed/assets/1185253/2d854eba-c4c4-4bce-b60b-dd250856b08f)

### Release notes
Release Notes:

- Fixed headers in multi-buffers overlapping over content of the buffer

Co-Authored-By: Antonio Scandurra <antonio@zed.dev>

Co-Authored-By: Antonio Scandurra <antonio@zed.dev>

This fixes block headers overlapping over text in the buffer when using
a custom line height of 1.25.

It fixes the issue by making the parent container a v-flex,
vertically-justifying the content and moving from relative padding to
absolute padding for the header itself.

Co-authored-by: antonio <antonio@zed.dev>
Co-authored-by: julia <julia@zed.dev>
Co-authored-by: marshall <marshall@zed.dev>

This reverts commit 5904bcf1c20638d63b244a1b2b038ec9a664ba1c.

Release Notes:

- N/A