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/_pagination.scss

@@ -0,0 +1,10 @@
+// Pagination
+
+// scss-docs-start pagination-mixin
+@mixin pagination-size($padding-y, $padding-x, $font-size, $border-radius) {
+  --#{$prefix}pagination-padding-x: #{$padding-x};
+  --#{$prefix}pagination-padding-y: #{$padding-y};
+  @include rfs($font-size, --#{$prefix}pagination-font-size);
+  --#{$prefix}pagination-border-radius: #{$border-radius};
+}
+// scss-docs-end pagination-mixin