[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.md

@@ -0,0 +1,70 @@
+# Kidekoop — Odoo 18.0 Custom Addons
+
+Odoo 18.0 (OCB community) addons repo. Code in **English**, UI in **Basque/Spanish**.
+Combines OCB (`ocb/`), inherited OCA addons, and our own custom addons.
+
+## ⚠️ Critical rules (non-negotiable)
+
+- **DO NOT modify** the OCB core (`ocb/`) nor these original OCA addons (reference/inheritance only):
+  `product_main_seller`, `product_origin`, `account_invoice_triple_discount`,
+  `product_get_price_helper`, `product_price_category`, `purchase_triple_discount`.
+  All changes go in our own custom addons.
+- **Do NOT use `_()` in field definitions** (triggers import-time warnings). Only in methods/executable code.
+- **Business logic ALWAYS on `product.product`** (variants), never on `product.template` (use `related` there).
+  Avoids issues with pricelists and reports that operate at the variant level.
+- **No logic in QWeb**: prepare all data in the Python controller; templates only do simple attribute access.
+- **No business logic in JavaScript**: UI/events only.
+- Translations: edit `.po` files with `polib` (append). **`msgmerge` corrupts the files** — do not use it.
+
+## Stack
+
+Odoo 18.0 · Python 3.10+ · PostgreSQL · Docker Compose · XML/QWeb/JS.
+Formatting: `black` (line 88) + `isort` (black profile) + `flake8` + `pylint-odoo`. Pre-commit active.
+
+## Commands
+
+```bash
+docker-compose up -d                                                   # env (8070=web, 8073=longpolling)
+docker-compose run odoo odoo -d odoo --test-enable --stop-after-init -u <addon>   # tests (run, NOT exec: avoids cache)
+docker-compose exec odoo odoo -d odoo -u <addon> --stop-after-init     # update addon
+docker-compose logs -f odoo                                            # logs
+docker-compose exec db psql -U odoo -d odoo                            # postgres
+make lint | make format | make check-format | make flake8 | make pylint-required
+pre-commit run --all-files
+```
+
+## Odoo conventions
+
+- Models `snake.case` · classes `PascalCase` · files `snake_case.py` · XML IDs `module.name`.
+- Manifest always `__manifest__.py`, version `18.0.X.Y.Z`, `depends` alphabetically ordered.
+- Views: 4 spaces, explicit `position` in XPath, groups via `module.xml_id`, `sequence` for ordering.
+- Bulk: prefer `search().write()` over loops; `create([vals, ...])` for bulk create.
+- Notifications: `ir.actions.client` + `display_notification`.
+- Detailed logging in price/discount computations: `_logger.info("[PRICE] ...", ...)`.
+- i18n: each addon ships `i18n/{es,eu}.po` (mandatory) + `.pot`. UTF-8 charset.
+
+## Custom addons
+
+- `product_sale_price_from_pricelist` — auto-computes sale price from last purchase price + pricelist.
+  Requires taxes on the product and `last_purchase_price_compute_type != "manual_update"`.
+- `website_sale_aplicoop` — Eskaera: collaborative purchasing for consumer co-ops (group orders,
+  per-member carts, cutoff/pickup dates, lazy loading, multi-language).
+- `account_invoice_triple_discount_readonly` — fix for triple-discount accumulation bug (always use it).
+- `product_price_category_supplier` — price categories per supplier.
+
+## Documentation
+
+- Per-addon details: its `README.rst` (OCA) or `README_DEV.md` (technical).
+- Global patterns: `.github/copilot-instructions.md` (extended version of this file).
+- Guides: `docs/QWEB_BEST_PRACTICES.md`, `docs/OCA_DOCUMENTATION.md`, `docs/LAZY_LOADING.md`.
+- OCA `readme/` structure (DESCRIPTION, INSTALL, CONFIGURE, USAGE, CONTRIBUTORS, CREDITS).
+  Credits: Criptomart (author) + Elika Bilbo (funder).
+
+## Commits
+
+`[TAG] module: description` — tags: `[ADD] [FIX] [IMP] [REF] [REM] [I18N] [DOC]`.
+
+## Available skills
+
+Per-language skills (`odoo-python`, `odoo-xml-views`, `odoo-qweb-html`, `odoo-javascript`) and the
+OpenSpec workflow (`openspec-explore/propose/apply-change/archive-change`, `/opsx:*` commands) live in `.claude/`.