feat: initial shared library extraction

Contains shared infrastructure for all coop services:
- shared/ (factory, urls, user_loader, context, internal_api, jinja_setup)
- models/ (User, Order, Calendar, Ticket, Product, Ghost CMS)
- db/ (SQLAlchemy async session, base)
- suma_browser/app/ (csrf, middleware, errors, authz, redis_cacher, payments, filters, utils)
- suma_browser/templates/ (shared base layouts, macros, error pages)
- static/ (CSS, JS, fonts, images)
- alembic/ (database migrations)
- config/ (app-config.yaml)
- editor/ (Lexical editor Node.js build)
- requirements.txt

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

config/app-config.yaml

@@ -0,0 +1,83 @@
+# App-wide settings
+base_host: "wholesale.suma.coop"
+base_login: https://wholesale.suma.coop/customer/account/login/
+base_url: https://wholesale.suma.coop/
+title: Rose Ash
+coop_root: /market
+coop_title: Market
+blog_root: /
+blog_title: all the news
+cart_root: /cart
+app_urls:
+  coop: "http://localhost:8000"
+  market: "http://localhost:8001"
+  cart: "http://localhost:8002"
+  events: "http://localhost:8003"
+cache:
+  fs_root: _snapshot  # <- absolute path to your snapshot dir
+categories:
+  allow:
+    Basics: basics
+    Branded Goods: branded-goods
+    Chilled: chilled
+    Frozen: frozen
+    Non-foods: non-foods
+    Supplements: supplements
+    Christmas: christmas
+slugs:
+  skip:
+    - ""
+    - customer
+    - account
+    - checkout
+    - wishlist
+    - sales
+    - contact
+    - privacy-policy
+    - terms-and-conditions
+    - delivery
+    - catalogsearch
+    - quickorder
+    - apply
+    - search
+    - static
+    - media
+section-titles:
+    - ingredients
+    - allergy information
+    - allergens
+    - nutritional information
+    - nutrition
+    - storage
+    - directions
+    - preparation
+    - serving suggestions
+    - origin
+    - country of origin
+    - recycling
+    - general information
+    - additional information
+    - a note about prices
+
+blacklist:
+  category:
+    - branded-goods/alcoholic-drinks
+    - branded-goods/beers
+    - branded-goods/wines
+    - branded-goods/ciders
+  product:
+    - list-price-suma-current-suma-price-list-each-bk012-2-html
+    - ---just-lem-just-wholefoods-jelly-crystals-lemon-12-x-85g-vf067-2-html
+  product-details:
+    - General Information
+    - A Note About Prices
+
+# SumUp payment settings (fill these in for live usage)
+sumup:
+  merchant_code: "ME4J6100"
+  currency: "GBP"
+  # Name of the environment variable that holds your SumUp API key
+  api_key_env: "SUMUP_API_KEY"
+  webhook_secret: "CHANGE_ME_TO_A_LONG_RANDOM_STRING"
+  checkout_reference_prefix: 'dev-'
+