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/purchase/static/description/icon.svg

@@ -0,0 +1 @@
+<svg width="50" height="50" viewBox="0 0 50 50" xmlns="http://www.w3.org/2000/svg"><path d="M0 12h50v26a4 4 0 0 1-4 4H0V12Z" fill="#985184"/><path d="M4 21a4 4 0 0 1-4-4v-5a4 4 0 0 1 4-4h46v9a4 4 0 0 1-4 4H4Z" fill="#1AD3BB"/><path d="M0 16h50v4a4 4 0 0 1-4 4H4a4 4 0 0 1-4-4v-4Z" fill="#005E7A"/></svg>