Add telemetry for user-facing notifications (#48558)

## Summary

Adds a "Notification Shown" telemetry event that fires whenever a
user-facing notification is displayed in Zed. This helps the team
understand error patterns, notification frequency, and which parts of
the application generate the most notifications.

## Event Schema

| Property | Type | Description |
|----------|------|-------------|
| `notification_type` | `string` | `"error"` or `"notification"` |
| `source` | `string` | Origin category (e.g., `lsp`, `git`, `settings`,
`editor`) |
| `lsp_name` | `string?` | Language server name (only for LSP
notifications) |
| `level` | `string?` | Severity: `"critical"`, `"warning"`, or `"info"`
|
| `has_actions` | `bool` | Whether the notification has action buttons |
| `notification_id` | `string` | Debug string of the NotificationId |
| `is_auto_dismissing` | `bool` | Whether the notification
auto-dismisses |

## NotificationSource Categories

A new `NotificationSource` enum categorizes notifications by origin:

- `lsp` - Language server notifications
- `settings` - Settings/keymap parse errors
- `update` - App updates, release notes
- `extension` - Extension suggestions/errors
- `git` - Git operations, commit errors
- `project` - Project-level issues
- `collab` - Collaboration notifications
- `remote` - SSH/remote project errors
- `file` - File access errors
- `editor` - Editor operations (search, encoding)
- `agent` - AI assistant notifications
- `cli` - CLI installation
- `system` - Generic fallback

## Privacy

**Message content is intentionally not included** in telemetry because:
- LSP messages come from external servers and may contain file paths or
error chains
- Error messages may contain sensitive paths or API-related information
- The metadata alone provides sufficient insight for error tracking

## Implementation

Updated function signatures to include `NotificationSource`:
- `show_notification(id, source, cx, build_fn)`
- `show_toast(toast, source, cx)`
- `show_error(err, source, cx)`
- `show_app_notification(id, source, cx, build_fn)`
- `notify_err(workspace, source, cx)`
- `notify_async_err(source, cx)`
- `notify_app_err(source, cx)`
- `detach_and_notify_err(source, window, cx)`

Release Notes

- N/A (internal telemetry change)

---------

Co-authored-by: Zed Zippy <234243425+zed-zippy[bot]@users.noreply.github.com>

crates/install_cli/src/install_cli_binary.rs

@@ -5,7 +5,7 @@ use release_channel::ReleaseChannel;
 use std::ops::Deref;
 use std::path::{Path, PathBuf};
 use util::ResultExt;
-use workspace::notifications::{DetachAndPromptErr, NotificationId};
+use workspace::notifications::{DetachAndPromptErr, NotificationId, NotificationSource};
 use workspace::{Toast, Workspace};
 
 actions!(
@@ -91,6 +91,7 @@ pub fn install_cli_binary(window: &mut Window, cx: &mut Context<Workspace>) {
                         ReleaseChannel::global(cx).display_name()
                     ),
                 ),
+                NotificationSource::Cli,
                 cx,
             )
         })?;