feat(invoices): remove client-facing PDF generation

Phase 1 / commit 11 of 14 — invoices are client-facing documents, and
per the new "no CRM-generated client-facing PDFs" rule (see the design
spec), the in-app pdfme rendering is removed entirely.

Future invoice rendering will use the deferred AcroForm-fill admin-
template feature: admin uploads a PDF template with named form fields,
CRM fills them with invoice data via pdf-lib. Same pattern as the
in-app EOI pathway. Tracked in BACKLOG.md.

Deleted:
  - src/lib/services/invoices.ts:generateInvoicePdf (60 LOC)
  - src/lib/pdf/templates/invoice-template.ts (entire pdfme template)
  - src/app/api/v1/invoices/[id]/generate-pdf/route.ts
  - src/components/invoices/invoice-pdf-preview.tsx (regenerate UI)
  - "PDF Preview" tab on invoice detail page
  - 5 now-unused imports in invoices.ts (files, ports, buildStoragePath,
    getStorageBackend, env)

sendInvoice() retained: still queues the send-invoice email job, still
flips status to "sent", still emits the socket event. The PDF-attach
step is gone — downstream consumers either render externally or wait
for the AcroForm-fill feature. The `pdfFileId` column on invoices stays
so existing rows don't break, just never gets written by this code path.

1319/1319 vitest green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/invoices/invoice-detail.tsx

@@ -23,7 +23,6 @@ import {
   SelectValue,
 } from '@/components/ui/select';
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
-import { InvoicePdfPreview } from './invoice-pdf-preview';
 import { apiFetch } from '@/lib/api/client';
 import { toastError } from '@/lib/api/toast-error';
 import { useMobileChrome } from '@/components/layout/mobile/mobile-layout-provider';
@@ -218,7 +217,6 @@ export function InvoiceDetail({ invoiceId }: InvoiceDetailProps) {
         <TabsList>
           <TabsTrigger value="overview">Overview</TabsTrigger>
           <TabsTrigger value="expenses">Linked Expenses</TabsTrigger>
-          <TabsTrigger value="pdf">PDF Preview</TabsTrigger>
           <TabsTrigger value="payment">Payment</TabsTrigger>
         </TabsList>
 
@@ -360,11 +358,6 @@ export function InvoiceDetail({ invoiceId }: InvoiceDetailProps) {
           )}
         </TabsContent>
 
-        {/* PDF Preview */}
-        <TabsContent value="pdf" className="pt-4">
-          <InvoicePdfPreview invoiceId={invoiceId} pdfFileId={invoice.pdfFileId} />
-        </TabsContent>
-
         {/* Payment */}
         <TabsContent value="payment" className="pt-4">
           {invoice.status === 'paid' ? (

src/components/invoices/invoice-pdf-preview.tsx

@@ -1,104 +0,0 @@
-'use client';
-
-import { useState } from 'react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
-import { Loader2, RefreshCw, FileText } from 'lucide-react';
-
-import { Button } from '@/components/ui/button';
-import { apiFetch } from '@/lib/api/client';
-
-interface InvoicePdfPreviewProps {
-  invoiceId: string;
-  pdfFileId?: string | null;
-}
-
-export function InvoicePdfPreview({
-  invoiceId,
-  pdfFileId: initialPdfFileId,
-}: InvoicePdfPreviewProps) {
-  const queryClient = useQueryClient();
-  const [pdfFileId, setPdfFileId] = useState(initialPdfFileId);
-
-  const { data: previewData, isLoading: previewLoading } = useQuery<{
-    url: string;
-    mimeType: string;
-  }>({
-    queryKey: ['file-preview', pdfFileId],
-    queryFn: () => apiFetch(`/api/v1/files/${pdfFileId}/preview`),
-    enabled: !!pdfFileId,
-  });
-
-  const regenerateMutation = useMutation({
-    mutationFn: () =>
-      apiFetch<{ data?: { id?: string } }>(`/api/v1/invoices/${invoiceId}/generate-pdf`, {
-        method: 'POST',
-      }),
-    onSuccess: (data) => {
-      const fileId = data?.data?.id;
-      if (fileId) {
-        setPdfFileId(fileId);
-        queryClient.invalidateQueries({ queryKey: ['invoices', invoiceId] });
-        queryClient.invalidateQueries({ queryKey: ['file-preview', fileId] });
-      }
-    },
-  });
-
-  if (!pdfFileId) {
-    return (
-      <div className="flex flex-col items-center justify-center gap-4 py-12 border border-dashed rounded-md">
-        <FileText className="h-10 w-10 text-muted-foreground" />
-        <p className="text-sm text-muted-foreground">No PDF generated yet</p>
-        <Button
-          variant="outline"
-          size="sm"
-          onClick={() => regenerateMutation.mutate()}
-          disabled={regenerateMutation.isPending}
-        >
-          {regenerateMutation.isPending ? (
-            <Loader2 className="mr-1.5 h-4 w-4 animate-spin" />
-          ) : (
-            <RefreshCw className="mr-1.5 h-4 w-4" />
-          )}
-          Generate PDF
-        </Button>
-      </div>
-    );
-  }
-
-  return (
-    <div className="space-y-3">
-      <div className="flex items-center justify-end">
-        <Button
-          variant="outline"
-          size="sm"
-          onClick={() => regenerateMutation.mutate()}
-          disabled={regenerateMutation.isPending}
-        >
-          {regenerateMutation.isPending ? (
-            <Loader2 className="mr-1.5 h-4 w-4 animate-spin" />
-          ) : (
-            <RefreshCw className="mr-1.5 h-4 w-4" />
-          )}
-          Regenerate PDF
-        </Button>
-      </div>
-
-      {previewLoading ? (
-        <div className="flex items-center justify-center py-12">
-          <Loader2 className="h-6 w-6 animate-spin text-muted-foreground" />
-        </div>
-      ) : previewData?.url ? (
-        <iframe
-          src={previewData.url}
-          className="w-full rounded border"
-          style={{ height: '600px' }}
-          title="Invoice PDF"
-        />
-      ) : (
-        <div className="flex items-center justify-center py-12 border rounded">
-          <p className="text-sm text-muted-foreground">Unable to load PDF preview</p>
-        </div>
-      )}
-    </div>
-  );
-}