Add web UI for WebDAV files and CardDAV contacts

Files browser (web/files):
- Alphabetical listing grouped folders-then-files
- Upload via button or drag-and-drop, including whole folders
- Folder creation
- Fixed layout for long filenames without spaces (table-fixed + break-all)

Contacts (web/contacts):
- Full CRUD for CardDAV contacts (create/edit/delete)
- VCF import (multi-card files) and export (single/all)
- Photo upload with preview, birthday field
- TYPE labels (private/business) for phone, email, address
- Repeatable multi-input rows for phones/emails/addresses instead of textareas
- Sanitizes a known malformed TYPE parameter pattern from some vCard
  exporters (e.g. Nextcloud Contacts) that otherwise caused phone numbers
  to be silently dropped on import

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

internal/web/templates/files.templ

@@ -0,0 +1,98 @@
+package templates
+
+// Breadcrumb is one segment of the current directory path shown above the
+// file listing, e.g. "docs" linking to "/web/files/docs/".
+type Breadcrumb struct {
+	Name string
+	Path string // relative path (no leading slash) used to build the link
+}
+
+// FileEntry is a single row (directory or file) in the file browser.
+type FileEntry struct {
+	Name     string
+	IsDir    bool
+	Size     string // human-readable, empty for directories
+	ModTime  string
+	RelPath  string // relative path (no leading slash) used to build the link
+}
+
+templ FilesPage(username string, breadcrumbs []Breadcrumb, entries []FileEntry, currentPath string) {
+	@Layout("Files", username) {
+		<div class="flex items-center justify-between mb-6 gap-4 flex-wrap">
+			<h1 class="text-2xl font-semibold">Files</h1>
+			<div class="flex gap-2">
+				<button id="new-folder-button" type="button"
+					class="bg-white border border-gray-300 rounded-md px-3 py-1.5 text-sm font-medium text-gray-700 hover:bg-gray-50">
+					New folder
+				</button>
+				<label class="cursor-pointer bg-indigo-600 text-white rounded-md px-3 py-1.5 text-sm font-medium hover:bg-indigo-700">
+					Upload files
+					<input id="upload-files-input" type="file" multiple class="hidden"/>
+				</label>
+				<label class="cursor-pointer bg-indigo-600 text-white rounded-md px-3 py-1.5 text-sm font-medium hover:bg-indigo-700">
+					Upload folder
+					<input id="upload-folder-input" type="file" webkitdirectory multiple class="hidden"/>
+				</label>
+			</div>
+		</div>
+
+		<nav class="text-sm text-gray-500 mb-4 flex flex-wrap items-center gap-1">
+			<a href="/web/files/" class="hover:underline text-indigo-600">home</a>
+			for _, bc := range breadcrumbs {
+				<span>/</span>
+				<a href={ templ.URL("/web/files/" + bc.Path + "/") } class="hover:underline text-indigo-600">{ bc.Name }</a>
+			}
+		</nav>
+
+		<div
+			id="file-drop-zone"
+			data-current-path={ currentPath }
+			data-upload-url={ "/web/files/" + currentPath }
+			class="bg-white rounded-lg border-2 border-dashed border-gray-200 p-2 transition-colors"
+		>
+			<table class="w-full text-sm table-fixed">
+				<colgroup>
+					<col class="w-auto"/>
+					<col class="w-20"/>
+					<col class="w-36"/>
+				</colgroup>
+				<thead>
+					<tr class="text-left text-gray-400 border-b border-gray-100">
+						<th class="py-2 px-3 font-medium">Name</th>
+						<th class="py-2 px-3 font-medium">Size</th>
+						<th class="py-2 px-3 font-medium">Modified</th>
+					</tr>
+				</thead>
+				<tbody>
+					for _, e := range entries {
+						<tr class="border-b border-gray-50 hover:bg-gray-50">
+							<td class="py-2 px-3 break-all">
+								if e.IsDir {
+									<a href={ templ.URL("/web/files/" + e.RelPath + "/") } class="flex items-center gap-2 text-indigo-600 hover:underline">
+										<span aria-hidden="true">📁</span>{ e.Name }
+									</a>
+								} else {
+									<a href={ templ.URL("/web/files/" + e.RelPath) } download class="flex items-center gap-2 text-gray-700 hover:underline">
+										<span aria-hidden="true">📄</span>{ e.Name }
+									</a>
+								}
+							</td>
+							<td class="py-2 px-3 text-gray-500 whitespace-nowrap">{ e.Size }</td>
+							<td class="py-2 px-3 text-gray-500 whitespace-nowrap">{ e.ModTime }</td>
+						</tr>
+					}
+					if len(entries) == 0 {
+						<tr>
+							<td colspan="3" class="py-6 px-3 text-center text-gray-400">
+								This folder is empty — drag &amp; drop files or folders here, or use the upload buttons above.
+							</td>
+						</tr>
+					}
+				</tbody>
+			</table>
+		</div>
+		<p id="upload-status" class="mt-3 text-sm text-gray-500"></p>
+		<script type="module" src="/web/static/files.js"></script>
+	}
+}
+