refactor(lsp): restructure lsp plugin controller architecture and simplify provider cache

- Replace LSPManager usage with LSPController integration
- Move UI access through lsp_controller.lsp_manager_ui
- Remove legacy ProviderResponseCache client management
- Simplify completion filtering and matcher handling
- Improve typing annotations and modernize union syntax
- Clean up unused imports and dead code
- Fix completion item parsing for insertText/textEdit fallbacks
- Add async-safe scrolling via GLib.idle_add

plugins/code/ui/lsp_manager/provider.py

@@ -22,7 +22,7 @@ class Provider(GObject.GObject, GtkSource.CompletionProvider):
     def __init__(self):
         super(Provider, self).__init__()
 
-        self.response_cache: ProviderResponseCache = ProviderResponseCache()
+        self.response_cache: ProviderResponseCache = None
 
 
     def pre_populate(self, context):
@@ -32,13 +32,19 @@ class Provider(GObject.GObject, GtkSource.CompletionProvider):
         return "LSP Code Completion"
 
     def do_match(self, context):
+        # Note: If provider is in interactive activation then need to check
+        # view focus as otherwise non focus views start trying to grab it.
+        # completion = context.get_property("completion")
+        # if not completion.get_view().has_focus(): return
+
         iter = self.response_cache.get_iter_correctly(context)
         iter.backward_char()
         ch = iter.get_char()
 
-        # NOTE: Look to re-add or apply supprting logic to use spaces
+        # NOTE: Look to re-add or apply supporting logic to use spaces
         # As is it slows down the editor in certain contexts...
-        if not (ch in ('_', '.', ' ') or ch.isalnum()):
+        # if not (ch in ('_', '.', ' ') or ch.isalnum()):
+        if not (ch in ('_', '.') or ch.isalnum()):
             return False
 
         buffer = iter.get_buffer()