Encrypt uploads in the browser and send them in chunks

A 6 GB upload kept a customer waiting long after its progress bar
reached 100%. The server wrote every upload three times: PHP's
temporary file, Livewire's copy of it ("Processing files...") and the
encrypted file ("Create Share Link"), each a full rewrite of a slow
disk. The unencrypted copy also stayed behind in livewire-tmp.

Now the uploader's browser encrypts each file in 16 MB chunks with
WebCrypto and PUTs them one at a time; the server checks each chunk in
memory and writes it once, already encrypted. Creating the share only
wraps its key and saves the options. A 200 MB upload through the
Docker image took 2.8 s, and its download matched byte for byte.

- SEALCHK2: a 19-byte header (chunk size, 7-byte nonce prefix), then
  ciphertext and tag per chunk. Each nonce holds the chunk index and a
  last-chunk flag (the STREAM construction), so cut or reordered files
  fail to decrypt. SEALCHK1 and the single-block format still read.
- Envelope encryption: one random key per share. With a password it is
  wrapped with Argon2id (sodium, libsodium's interactive limits) in
  shares.wrapped_key, which names its parameters. Password shares from
  before keep their PBKDF2-derived key.
- The upload page registers each selection with FileUploader into a
  pending share of its own, lists the files with their progress, retries
  a failed chunk after 1-16 s, then offers Retry; Remove and Cancel
  abort. UploadChunkController only accepts chunks from the session that
  started the share: a repeat is acknowledged, a skip gets 409 with the
  count stored. Chunks go out as Blobs, which Chromium sends about eight
  times faster than ArrayBuffers.
- Uploads need a secure context: over plain HTTP the page says HTTPS is
  needed and takes no files. The Docker image gains AUTO_HTTPS, which
  serves Let's Encrypt on 443 for SERVER_NAME and redirects 80; without
  it the container stays on HTTP 80 behind a proxy. docker/Caddyfile was
  never loaded and is gone; docker/healthcheck.sh covers both modes.
- "Download all" streams the ZIP with maennchen/zipstream-php (STORE,
  ZIP64) instead of decrypting whole files into memory and writing the
  archive unencrypted to /tmp.
- Pending shares count towards the quota, stay out of the admin
  dashboard and 404 everywhere else. shares:cleanup deletes uploads idle
  for 4 hours and Livewire temporary files older than that.
- PHP's upload limits no longer cap the admin's max file size and
  default to 64M; LIVEWIRE_MAX_UPLOAD_TIME is gone and
  UPLOAD_CHUNK_SIZE_MB is new.
- Tests cover the format, key wrapping, registration limits, the chunk
  endpoint's answers, completing a share, the streamed ZIP, cleanup,
  and in Chromium a real chunked upload and the HTTPS warning; the
  selected-files overflow test runs again. README, website, CHANGELOG
  and .ai/rules follow.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/Livewire/Admin/AdminDashboard.php

@@ -43,18 +43,20 @@ class AdminDashboard extends Component
         $column = in_array($this->sortBy['column'] ?? null, self::SORTABLE, true) ? $this->sortBy['column'] : 'created_at';
         $direction = ($this->sortBy['direction'] ?? null) === 'asc' ? 'asc' : 'desc';
 
+        // Shares whose files are still being uploaded are not shares yet; their bytes do count as used space.
         $shares = Share::query()
+            ->whereNotNull('completed_at')
             ->withCount('files')
             ->orderBy($column, $direction)
             ->paginate(15);
 
         return view('livewire.admin.admin-dashboard', [
             'shares' => $shares,
-            'totalShares' => Share::query()->count(),
-            'activeShares' => Share::query()->where(function ($q) {
+            'totalShares' => Share::query()->whereNotNull('completed_at')->count(),
+            'activeShares' => Share::query()->whereNotNull('completed_at')->where(function ($q) {
                 $q->whereNull('expires_at')->orWhere('expires_at', '>', now());
             })->count(),
-            'totalFiles' => ShareFile::query()->count(),
+            'totalFiles' => ShareFile::query()->whereHas('share', fn ($query) => $query->whereNotNull('completed_at'))->count(),
             'usedSpace' => $shareService->getTotalUsedSpace(),
             'maxQuota' => $shareService->getMaxStorageQuota(),
         ]);