Add namespace qualifier highlighting

[alfredomtx]

Summary

Dims namespace qualifiers in inline FQNs using @label capture, matching IDE behavior like PhpStorm.

Before: \App\Models\User - all same color
After: \App\Models\ - dimmed, User - highlighted

Changes

Targets specific expression contexts where inline FQNs appear:

• Class constant access: \App\Models\Foo::CONST
• Static method calls: \App\Models\Foo::method()
• Object creation: new \App\Models\Foo()
• Type annotations

use statements are NOT affected.

Theme Configuration

"theme_overrides": {
  "One Light": {
    "syntax": {
      "label": { "color": "#a0a1a7" }
    }
  }
}

Example:

[alfredomtx]

I'm closing it because I'm not sure this will be useful for the community.
I was trying to achieve the same behaviour as PhpStorm, to only dim the full namespace when it can be replaced by an import(code action), but it doesn't seem that this is currently possible on Zed.