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>

static/nav-labels/new.svg

@@ -0,0 +1,14 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+     viewBox="0 0 100 100" width="100" height="100" role="img" aria-labelledby="title">
+  <title id="title">New</title>
+
+    <!-- The stripe -->
+    <rect x="0" y="30" width="100" height="40" rx="4" fill="#22c55e"/>
+    <!-- Label on the stripe (centered) -->
+    <text x="52" y="52"
+          font-family="system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif"
+          font-size="25" font-weight="800" fill="#ffffff"
+          text-anchor="middle" dominant-baseline="middle" letter-spacing=".15em">
+      NEW
+    </text>
+</svg>

static/nav-labels/offer.svg

@@ -0,0 +1,16 @@
+
+
+<svg xmlns="http://www.w3.org/2000/svg"
+     viewBox="0 0 100 100" width="100" height="100" role="img" aria-labelledby="title">
+  <title id="title">Offer</title>
+
+    <!-- The stripe -->
+    <rect x="0" y="30" width="100" height="40" rx="4" fill="#22c55e"/>
+    <!-- Label on the stripe (centered) -->
+    <text x="52" y="52"
+          font-family="system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif"
+          font-size="25" font-weight="800" fill="#ffffff"
+          text-anchor="middle" dominant-baseline="middle" letter-spacing=".15em">
+      OFFER
+    </text>
+</svg>