Eliminate Python dependency: embed frontend assets in odoo-go

- Copy all OWL frontend assets (JS/CSS/XML/fonts/images) into frontend/
  directory (2925 files, 43MB) — no more runtime reads from Python Odoo
- Replace OdooAddonsPath config with FrontendDir pointing to local frontend/
- Rewire bundle.go, static.go, templates.go, webclient.go to read from
  frontend/ instead of external Python Odoo addons directory
- Auto-detect frontend/ and build/ dirs relative to binary in main.go
- Delete obsolete Python helper scripts (tools/*.py)

The Go server is now fully self-contained: single binary + frontend/ folder.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/web/static/lib/bootstrap/scss/mixins/_caret.scss

@@ -0,0 +1,69 @@
+// scss-docs-start caret-mixins
+@mixin caret-down($width: $caret-width) {
+  border-top: $width solid;
+  border-right: $width solid transparent;
+  border-bottom: 0;
+  border-left: $width solid transparent;
+}
+
+@mixin caret-up($width: $caret-width) {
+  border-top: 0;
+  border-right: $width solid transparent;
+  border-bottom: $width solid;
+  border-left: $width solid transparent;
+}
+
+@mixin caret-end($width: $caret-width) {
+  border-top: $width solid transparent;
+  border-right: 0;
+  border-bottom: $width solid transparent;
+  border-left: $width solid;
+}
+
+@mixin caret-start($width: $caret-width) {
+  border-top: $width solid transparent;
+  border-right: $width solid;
+  border-bottom: $width solid transparent;
+}
+
+@mixin caret(
+  $direction: down,
+  $width: $caret-width,
+  $spacing: $caret-spacing,
+  $vertical-align: $caret-vertical-align
+) {
+  @if $enable-caret {
+    &::after {
+      display: inline-block;
+      margin-left: $spacing;
+      vertical-align: $vertical-align;
+      content: "";
+      @if $direction == down {
+        @include caret-down($width);
+      } @else if $direction == up {
+        @include caret-up($width);
+      } @else if $direction == end {
+        @include caret-end($width);
+      }
+    }
+
+    @if $direction == start {
+      &::after {
+        display: none;
+      }
+
+      &::before {
+        display: inline-block;
+        margin-right: $spacing;
+        vertical-align: $vertical-align;
+        content: "";
+        @include caret-start($width);
+      }
+    }
+
+    &:empty::after {
+      margin-left: 0;
+    }
+  }
+}
+// scss-docs-end caret-mixins