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/collaborators.go

@@ -309,6 +309,63 @@ func (h *collaboratorHandler) cancelInvite(w http.ResponseWriter, r *http.Reques
 	w.WriteHeader(http.StatusNoContent)
 }
 
+// --- "your pending invites" (self-service inbox) ---
+
+// GET /me/invites — authed. Lists invites addressed to the caller's email
+// so the dashboard can show a one-click Accept banner without requiring
+// the user to re-click the email link. Crucial for the signup → verify-
+// email → login flow where the email click opens a new tab and the
+// original invite tab is forgotten.
+func (h *collaboratorHandler) myInvites(w http.ResponseWriter, r *http.Request) {
+	userID, ok := hostFromContext(w, r)
+	if !ok {
+		return
+	}
+	user, err := h.users.GetByID(r.Context(), userID)
+	if err != nil || user == nil {
+		writeError(w, http.StatusUnauthorized, "unauthenticated")
+		return
+	}
+	pending, err := h.invites.ListPendingForEmail(r.Context(), user.Email)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to list invites")
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"invites": pending})
+}
+
+// POST /me/invites/{event_id}/accept — authed. Accepts the latest pending
+// invite for (caller.email, event_id). Same effect as POST /invites/{token}/
+// accept but doesn't require the raw token; the caller's verified email is
+// the identity signal instead.
+func (h *collaboratorHandler) acceptForEvent(w http.ResponseWriter, r *http.Request) {
+	userID, ok := hostFromContext(w, r)
+	if !ok {
+		return
+	}
+	user, err := h.users.GetByID(r.Context(), userID)
+	if err != nil || user == nil {
+		writeError(w, http.StatusUnauthorized, "unauthenticated")
+		return
+	}
+	eventID, ok := parseIDParam(w, r, "event_id")
+	if !ok {
+		return
+	}
+	role, err := h.collabs.AcceptByEventAndEmail(r.Context(), eventID, user.Email, userID)
+	if err != nil {
+		switch {
+		case errors.Is(err, domain.ErrInviteNotFound):
+			writeError(w, http.StatusNotFound, "no pending invitation for this event")
+		default:
+			h.logger.Error("accept by email", "err", err)
+			writeError(w, http.StatusInternalServerError, "failed to accept invitation")
+		}
+		return
+	}
+	writeJSON(w, http.StatusOK, acceptResponse{EventID: eventID, Role: role})
+}
+
 // --- public invite-accept flow ---
 
 type inviteSummary struct {