feat(tier2): event branding + UX polish — Block D

Backend
- Migration 0010 adds event_branding (one row per event; all fields
  nullable so a brand-new event renders with defaults)
- BrandingRepo with COALESCE/NULLIF upsert semantics: nil pointer
  preserves the existing value, "" clears the field to NULL
- internal/uploads package: ImageStore interface + LocalFSStore (dev),
  pure-stdlib decode + re-encode that strips EXIF and rejects anything
  that isn't valid JPEG/PNG. Size cap 2 MB, random 16-byte filenames
- GET /events/{id}/branding (viewer+) returns the row plus the
  AllowedFonts list so the frontend picker stays in sync
- PUT /events/{id}/branding (editor+) validates hex colours, font
  allowlist, and refuses image URLs whose path doesn't start with
  /uploads/ (blocks arbitrary-origin <img> smuggling on guest pages)
- POST /uploads/image (authed) → fresh CDN URL; GET /uploads/{file}
  serves with year-long cache (immutable random names)
- GET /access/{token} now embeds the host's branding so the RSVP page
  can render in their colours/font with their logo + cover
- docker-compose mounts a named volume for uploads
- Custom-domain sub-block deferred to Tier 3 per the plan

Frontend
- BrandingCard.vue: colour pickers, font dropdown, logo + cover upload
  with progressive disclosure, live preview pane that re-renders on
  every keystroke
- RSVP page applies branding via CSS vars at the section root, so
  primary colour theme + font cascade through every child card. Cover
  image renders as a banner above the form; logo lands in the header
- Submit button background switches to var(--brand-primary) when set
- Mounted on the event detail page below the guests block

Plus the small UX fixes from the e2e walkthrough:
- Nav: dropped the top-level "Events" link; the logo doubles as the
  home affordance (→ /dashboard when signed in, → / otherwise). Account
  + Billing + Sign out live under a profile dropdown (avatar with
  initials, opens on click, closes on outside-click / Esc / route nav)
- Renamed "Back to dashboard" → "Back to events" across event detail,
  billing, account, and new-event pages

Tests
- TestBrandingGetReturnsDefaults / TestBrandingPutPersists /
  TestBrandingPutRejectsBadInputs / TestUploadAndServeImage /
  TestUploadRejectsNonImage — all pass
- Domain tests for IsValidHexColor + IsAllowedFont
- Full integration suite green (176s)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/api/events.go

@@ -125,23 +125,36 @@ func (h *eventHandler) list(w http.ResponseWriter, r *http.Request) {
 	offset := atoiOr(q.Get("offset"), 0)
 
 	// Block C: the dashboard shows every event the user has any role on,
-	// not just events they own. The collaborators repo gives us the id set;
-	// the events repo paginates the merged list.
-	collabIDs, err := h.collabs.ListEventIDsForUser(r.Context(), hostID)
+	// not just events they own. Pull the role map up front so we can
+	// annotate each card with `your_role` — the frontend uses that to
+	// split "your events" from "shared with you" without a follow-up call.
+	roles, err := h.collabs.RolesForUser(r.Context(), hostID)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, "failed to resolve memberships")
 		return
 	}
+	collabIDs := make([]uuid.UUID, 0, len(roles))
+	for id := range roles {
+		collabIDs = append(collabIDs, id)
+	}
 	events, err := h.repo.ListForUser(r.Context(), hostID, collabIDs, limit, offset)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, "failed to list events")
 		return
 	}
-	if events == nil {
-		events = []*domain.Event{}
+	views := make([]eventView, 0, len(events))
+	for _, ev := range events {
+		role := roles[ev.ID]
+		if role == "" && ev.HostID == hostID {
+			// Defensive: legacy events created before Block C's seed-on-
+			// create may not have a collaborator row. Fall back to the
+			// host_id check so they still show as owned.
+			role = domain.RoleOwner
+		}
+		views = append(views, eventView{Event: ev, YourRole: role})
 	}
 	writeJSON(w, http.StatusOK, map[string]any{
-		"events": events,
+		"events": views,
 		"limit":  limit,
 		"offset": offset,
 	})