[ADD] Claude Code ecosystem adapted from Copilot config

Port .github Copilot setup to Claude Code:
- CLAUDE.md: condensed project instructions (auto-loaded each session)
- .claude/skills: per-language guides (odoo-python, odoo-xml-views,
  odoo-qweb-html, odoo-javascript) + openspec-* workflow skills
- .claude/commands/opsx: /opsx:explore|propose|apply|archive slash commands

Original .github/ files kept untouched as extended reference.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.claude/skills/odoo-xml-views/SKILL.md

@@ -0,0 +1,28 @@
+---
+name: odoo-xml-views
+description: XML/Odoo views conventions for this repo (XPath, inheritance, IDs, security, manifest data). Use when editing .xml views, security/, or XML data in Odoo addons.
+metadata:
+  type: reference
+---
+
+# XML (Odoo Views)
+
+## Style and conventions
+- Indentation: **4 spaces** (no tabs).
+- XPath with explicit `position`: `before`, `after`, `inside`, `replace`, `attributes`.
+- Reference groups via `module.xml_id` (e.g. `sales_team.group_sale_manager`).
+- `sequence` to order fields in views.
+- IDs: `module.descriptive_name` pattern.
+- **No conditional logic in QWeb**, only access to attributes prepared in the controller.
+- Translate strings in XML, never with `_()` in Python field definitions.
+
+## Key patterns
+- Views in `views/*.xml`. Typical manifest `data` order:
+  `security/ir.model.access.csv`, `views/actions.xml`, `views/menu.xml`, `views/<model>_views.xml`.
+- Security: `id,name,model_id:id,group_id:id,perm_read,perm_write,perm_create,perm_unlink`.
+- Common groups: `base.group_user`, `base.group_system`,
+  `sales_team.group_sale_manager`, `purchase.group_purchase_manager`.
+
+## Common mistakes
+- *XPath not found* → check inheritance chain and correct XML IDs.
+- Complex logic in QWeb → move it to the controller (see `docs/QWEB_BEST_PRACTICES.md`).