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/src/xml/inventory_lines.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<templates id="template" xml:space="preserve">
+    <t t-name="InventoryLines.Buttons">
+        <button type="button" class='btn btn-primary o_button_validate_inventory'>
+            Validate Inventory
+        </button>
+    </t>
+</templates>

frontend/stock/static/src/xml/report_stock_reception.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<templates id="template" xml:space="preserve">
+
+<t t-name="reception_report_buttons">
+    <button
+        name="assign_all_link"
+        class="btn btn-secondary o_report_reception_assign o_assign_all">
+        Assign All
+    </button>
+    <button
+        name="print_all_labels"
+        class="btn btn-secondary o_print_label o_print_label_all">
+        Print Labels
+    </button>
+</t>
+</templates>