refactor(semantics): migrate legacy @TIER to @COMPLEXITY annotations

- Replaced @TIER: TRIVIAL with @COMPLEXITY: 1
- Replaced @TIER: STANDARD with @COMPLEXITY: 3
- Replaced @TIER: CRITICAL with @COMPLEXITY: 5
- Manually elevated specific critical/complex components to levels 2 and 4
- Ignored legacy, specs, and node_modules directories
- Updated generated semantic map

frontend/src/lib/ui/Button.svelte

@@ -1,6 +1,6 @@
 <!-- [DEF:Button:Component] -->
 <!--
-@TIER: TRIVIAL
+@COMPLEXITY: 1
 @SEMANTICS: button, ui-atom, interactive
 @PURPOSE:   Standardized button component with variants and loading states.
 @LAYER:     Atom

frontend/src/lib/ui/Card.svelte

@@ -1,6 +1,6 @@
 <!-- [DEF:Card:Component] -->
 <!--
-@TIER: TRIVIAL
+@COMPLEXITY: 1
 @SEMANTICS: card, container, ui-atom
 @PURPOSE:   Standardized container with padding and elevation.
 @LAYER:     Atom

frontend/src/lib/ui/Input.svelte

@@ -1,6 +1,6 @@
 <!-- [DEF:Input:Component] -->
 <!--
-@TIER: TRIVIAL
+@COMPLEXITY: 1
 @SEMANTICS: input, form-field, ui-atom
 @PURPOSE:   Standardized text input component with label and error handling.
 @LAYER:     Atom

frontend/src/lib/ui/LanguageSwitcher.svelte

@@ -1,6 +1,6 @@
 <!-- [DEF:LanguageSwitcher:Component] -->
 <!--
-@TIER: TRIVIAL
+@COMPLEXITY: 1
 @SEMANTICS: language-switcher, i18n-ui, ui-atom
 @PURPOSE:   Dropdown component to switch between supported languages.
 @LAYER:     Atom

frontend/src/lib/ui/PageHeader.svelte

@@ -1,6 +1,6 @@
 <!-- [DEF:PageHeader:Component] -->
 <!--
-@TIER: TRIVIAL
+@COMPLEXITY: 1
 @SEMANTICS: page-header, layout-atom
 @PURPOSE:   Standardized page header with title and action area.
 @LAYER:     Atom

frontend/src/lib/ui/Select.svelte

@@ -1,6 +1,6 @@
 <!-- [DEF:Select:Component] -->
 <!--
-@TIER: TRIVIAL
+@COMPLEXITY: 1
 @SEMANTICS: select, dropdown, form-field, ui-atom
 @PURPOSE:   Standardized dropdown selection component.
 @LAYER:     Atom

frontend/src/lib/ui/index.ts

@@ -1,6 +1,6 @@
 // [DEF:ui:Module]
 //
-// @TIER: TRIVIAL
+// @COMPLEXITY: 1
 // @SEMANTICS: ui, components, library, atomic-design
 // @PURPOSE:   Central export point for standardized UI components.
 // @LAYER:     Atom