Add Billet entity, BilletDesign, ticket designer, CRUD billets, commissions

- Create Billet entity: name, position, priceHT, quantity (nullable=unlimited),
  isGeneratedBillet, hasDefinedExit, notBuyable, type (billet/reservation_brocante/vote),
  stripeProductId, description, picture (VichUploader), category (ManyToOne CASCADE)
- Create BilletDesign entity (OneToOne Event): accentColor, invitationTitle, invitationColor
- Billet CRUD: add/edit/delete with access control, Stripe product sync on connected account
- Billet reorder: drag & drop with position field, refactored sortable.js for both categories and billets
- Ticket designer tab (custom offer only): accent color, invitation title/color, live iframe preview
- A4 ticket preview: 4 zones (HG infos+billet, HD affiche, BG association, BD sortie+invitation), fake QR code SVG
- Commission calculator JS: live breakdown of E-Ticket fee, Stripe fee (1.5%+0.25EUR), net amount
- Sales recap on categories tab: qty sold, total HT, total commissions, total net
- DisableProfilerSubscriber: disable web profiler toolbar on preview iframe
- CSP: allow self in frame-src and frame-ancestors for preview iframe
- Flysystem: dedicated billets.storage for billet images
- Upload accept restricted to png/jpeg/webp/gif (no HEIC)
- Makefile: add force_sql_dev command
- CLAUDE.md: add rule to never modify existing migrations
- Consolidate all migrations into single Version20260321111125
- Tests: BilletTest (20), BilletDesignTest (6), DisableProfilerSubscriberTest (5),
  billet-designer.test.js (7), commission-calculator.test.js (7),
  AccountControllerTest billet CRUD tests (11)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

assets/modules/billet-designer.js

@@ -0,0 +1,64 @@
+export function initBilletDesigner() {
+    const designer = document.getElementById('billet-designer')
+    if (!designer) return
+
+    const previewUrl = designer.dataset.previewUrl
+    const saveUrl = designer.dataset.saveUrl
+    if (!previewUrl) return
+
+    const iframe = document.getElementById('billet-preview-frame')
+    const reloadBtn = document.getElementById('billet-reload-preview')
+    const saveBtn = document.getElementById('billet-save-design')
+    if (!iframe) return
+
+    const inputs = designer.querySelectorAll('input[name]')
+
+    function buildPreviewUrl() {
+        const params = new URLSearchParams()
+
+        for (const input of inputs) {
+            if (input.type === 'checkbox') {
+                params.set(input.name, input.checked ? '1' : '0')
+            } else {
+                params.set(input.name, input.value)
+            }
+        }
+
+        return previewUrl + '?' + params.toString()
+    }
+
+    function reloadPreview() {
+        iframe.src = buildPreviewUrl()
+    }
+
+    function saveDesign() {
+        if (!saveUrl) return
+
+        const formData = new FormData()
+        for (const input of inputs) {
+            if (input.type === 'checkbox') {
+                formData.set(input.name, input.checked ? '1' : '0')
+            } else {
+                formData.set(input.name, input.value)
+            }
+        }
+
+        globalThis.fetch(saveUrl, {
+            method: 'POST',
+            body: formData,
+        })
+    }
+
+    for (const input of inputs) {
+        input.addEventListener('input', reloadPreview)
+        input.addEventListener('change', reloadPreview)
+    }
+
+    if (reloadBtn) {
+        reloadBtn.addEventListener('click', reloadPreview)
+    }
+
+    if (saveBtn) {
+        saveBtn.addEventListener('click', saveDesign)
+    }
+}