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/stock/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="m25 4 6.857 4L15.5 19v16l.5 5.75-9-5.25v-21L25 4Z" fill="#FBB945"/><path d="m18.087 41.967-6.138-3.58V17.5L30.046 6.943l6.283 3.665L22.001 23.5l-3.915 18.467Z" fill="#F86126"/><path d="M36.328 10.61 43 14.5v21L25 46l-6.914-4.032V21.25l18.242-10.642Z" fill="#985184"/></svg>