Add favicon and enable sorting on all table columns

- Add custom Orchard favicon (tree with apples)
- Simplify browser tab title to "Orchard"
- Enable sorting on all columns except description:
  - Home: name, visibility, owner, created, updated
  - Project: name, format, tags, artifacts, size, created
  - Package: tag, size, type, filename, created
- Fix column keys to match API field names for proper sorting

frontend/src/pages/Home.tsx

@@ -234,6 +234,7 @@ function Home() {
             {
               key: 'visibility',
               header: 'Visibility',
+              sortable: true,
               render: (project) => (
                 <Badge variant={project.is_public ? 'public' : 'private'}>
                   {project.is_public ? 'Public' : 'Private'}
@@ -243,6 +244,7 @@ function Home() {
             {
               key: 'created_by',
               header: 'Owner',
+              sortable: true,
               className: 'cell-owner',
               render: (project) => project.created_by,
             },

frontend/src/pages/PackagePage.tsx

@@ -193,20 +193,23 @@ function PackagePage() {
       ),
     },
     {
-      key: 'size',
+      key: 'artifact_size',
       header: 'Size',
+      sortable: true,
       render: (t: TagDetail) => <span>{formatBytes(t.artifact_size)}</span>,
     },
     {
-      key: 'content_type',
+      key: 'artifact_content_type',
       header: 'Type',
+      sortable: true,
       render: (t: TagDetail) => (
         <span className="content-type">{t.artifact_content_type || '-'}</span>
       ),
     },
     {
-      key: 'original_name',
+      key: 'artifact_original_name',
       header: 'Filename',
+      sortable: true,
       className: 'cell-truncate',
       render: (t: TagDetail) => (
         <span title={t.artifact_original_name || undefined}>{t.artifact_original_name || '-'}</span>

frontend/src/pages/ProjectPage.tsx

@@ -327,21 +327,25 @@ function ProjectPage() {
             {
               key: 'format',
               header: 'Format',
+              sortable: true,
               render: (pkg) => <Badge variant="default">{pkg.format}</Badge>,
             },
             {
-              key: 'tags',
+              key: 'tag_count',
               header: 'Tags',
+              sortable: true,
               render: (pkg) => pkg.tag_count ?? '—',
             },
             {
-              key: 'artifacts',
+              key: 'artifact_count',
               header: 'Artifacts',
+              sortable: true,
               render: (pkg) => pkg.artifact_count ?? '—',
             },
             {
-              key: 'size',
+              key: 'total_size',
               header: 'Size',
+              sortable: true,
               render: (pkg) =>
                 pkg.total_size !== undefined && pkg.total_size > 0 ? formatBytes(pkg.total_size) : '—',
             },