Add design system, audit sections, apply global classes

Design system (design/):
- bcw-css-variables.json: color, spacing (--space-xs→2xl), typography (--h1→h6, --text-sm→xl)
- bcw-color-palette.json: named swatches referencing CSS variables
- bcw-global-classes.json: section-container, section-header, col-3, col-4, features-container, footer-sub-section
- design.md: full variable reference and usage guide

Templates:
- features-3col + features-4col: add global_classes embed + _cssGlobalClasses references
- All headers + footers: apply var(--color-primary) background to section elements
- footer-columns: add footer-sub-section class to column containers
- Remove content-image-left (duplicate of content-image-right with children reversed)
- testimonials: gap tweak 12px → 15px on card containers

Repo hygiene:
- Add .gitignore (Updated_Sections/)
- Clear Updated_Sections staging folder

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

footers/footer-columns.json

@@ -2,13 +2,30 @@
   "title": "BCW — Footer Columns",
   "type": "footer",
   "templateType": "footer",
+  "global_classes": [
+    {
+      "id": "footer-sub-section",
+      "name": "footer-sub-section",
+      "settings": {
+        "_rowGap": "15px"
+      },
+      "modified": 1772146505,
+      "user_id": 2
+    }
+  ],
   "footer": [
     {
       "id": "sec001",
       "name": "section",
       "parent": 0,
       "children": ["con001"],
-      "settings": [],
+      "settings": {
+        "_background": {
+          "color": {
+            "raw": "var(--color-primary)"
+          }
+        }
+      },
       "label": "Footer Columns"
     },
     {
@@ -31,7 +48,8 @@
       "settings": {
         "_direction": "column",
         "_alignItems": "flex-start",
-        "_gap": "16px"
+        "_gap": "16px",
+        "_cssGlobalClasses": ["footer-sub-section"]
       },
       "label": "About Column"
     },
@@ -63,7 +81,8 @@
       "settings": {
         "_direction": "column",
         "_alignItems": "flex-start",
-        "_gap": "16px"
+        "_gap": "16px",
+        "_cssGlobalClasses": ["footer-sub-section"]
       },
       "label": "Links Column"
     },
@@ -92,7 +111,8 @@
       "settings": {
         "_direction": "column",
         "_alignItems": "flex-start",
-        "_gap": "12px"
+        "_gap": "12px",
+        "_cssGlobalClasses": ["footer-sub-section"]
       },
       "label": "Contact Column"
     },

footers/footer-minimal.json

@@ -8,7 +8,13 @@
       "name": "section",
       "parent": 0,
       "children": ["con001"],
-      "settings": [],
+      "settings": {
+        "_background": {
+          "color": {
+            "raw": "var(--color-primary)"
+          }
+        }
+      },
       "label": "Footer Minimal"
     },
     {