Refactor code completion, container layouts, and webkit settings

- Renamed alt_provider.py file under words completer
- Improve word completion matching logic with character validation
- Change container orientations (header→vertical, left/right→horizontal)
- Add separators to all container edges
- Refactor webkit UI loading into separate load_url/load_context_base_path methods
- Add comprehensive webkit browser-like settings

plugins/code/completers/words_completer/default_provider.py

@@ -0,0 +1,68 @@
+# Python imports
+import re
+
+# Lib imports
+import gi
+gi.require_version('Gtk', '3.0')
+gi.require_version('GtkSource', '4')
+
+from gi.repository import GObject
+from gi.repository import Gtk
+from gi.repository import GtkSource
+
+# Application imports
+from .provider_response_cache import ProviderResponseCache
+
+
+
+class Provider(GtkSource.CompletionWords):
+    """
+        This is a Words Completion Provider.
+        # NOTE: used information from here --> https://warroom.rsmus.com/do-that-auto-complete/
+    """
+    __gtype_name__ = 'WordsCompletionProvider'
+
+    def __init__(self):
+        super(Provider, self).__init__()
+
+        self.response_cache: ProviderResponseCache = ProviderResponseCache()
+
+
+    def do_get_name(self):
+        return 'Words 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
+
+        word = self.response_cache.get_word(context)
+        if not word or len(word) < 2: return False
+
+        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
+        # As is it slows down the editor in certain contexts...
+        # if not (ch in ('_', '.', ' ') or ch.isalnum()):
+        if not (ch in ('_', '.') or ch.isalnum()):
+            return False
+
+        return True
+
+    def do_get_priority(self):
+        return 0
+
+    def do_activate_proposal(self, proposal, iter_):
+        buffer = iter_.get_buffer()
+        # Note: Flag mostly intended for SourceViewsMultiInsertState
+        #       to insure marker processes inserted text correctly.
+        buffer.is_processing_completion = True
+        return False
+
+    def do_get_activation(self):
+        """ The context for when a provider will show results """
+        # return GtkSource.CompletionActivation.NONE
+        # return GtkSource.CompletionActivation.USER_REQUESTED
+        return GtkSource.CompletionActivation.INTERACTIVE