Initial commit: notification-elements-demo app

Interactive Angular 19 demo for @sda/notification-elements-ui with
6 sections: Bell & Feed, Notification Center, Inbox, Comments &
Threads, Mention Input, and Full-Featured layout. Includes mock
data, dark mode toggle, and real-time event log.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

node_modules/which/README.md

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+# which
+
+Like the unix `which` utility.
+
+Finds the first instance of a specified executable in the PATH
+environment variable.  Does not cache the results, so `hash -r` is not
+needed when the PATH changes.
+
+## USAGE
+
+```javascript
+const which = require('which')
+
+// async usage
+// rejects if not found
+const resolved = await which('node')
+
+// if nothrow option is used, returns null if not found
+const resolvedOrNull = await which('node', { nothrow: true })
+
+// sync usage
+// throws if not found
+const resolved = which.sync('node')
+
+// if nothrow option is used, returns null if not found
+const resolvedOrNull = which.sync('node', { nothrow: true })
+
+// Pass options to override the PATH and PATHEXT environment vars.
+await which('node', { path: someOtherPath, pathExt: somePathExt })
+```
+
+## CLI USAGE
+
+Just like the BSD `which(1)` binary but using `node-which`.
+
+```
+usage: node-which [-as] program ...
+```
+
+You can learn more about why the binary is `node-which` and not `which` 
+[here](https://github.com/npm/node-which/pull/67)
+
+## OPTIONS
+
+You may pass an options object as the second argument.
+
+- `path`: Use instead of the `PATH` environment variable.
+- `pathExt`: Use instead of the `PATHEXT` environment variable.
+- `all`: Return all matches, instead of just the first one.  Note that
+  this means the function returns an array of strings instead of a
+  single string.