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/src/views/purchase_listview.xml

@@ -0,0 +1,13 @@
+<templates>
+    <t t-name="purchase.ListRenderer" t-inherit="account.FileUploadListRenderer" t-inherit-mode="primary">
+        <xpath expr="//div[hasclass('o_list_renderer')]" position="before">
+            <PurchaseDashBoard list="props.list"/>
+        </xpath>
+    </t>
+
+    <t t-name="purchase.ListView" t-inherit="web.ListView" t-inherit-mode="primary">
+        <xpath expr="//SelectionBox" position="after">
+            <PurchaseFileUploader list="model.root"/>
+        </xpath>
+    </t>
+</templates>