Add URL content type support and enhance snippet functionality:

- Introduced 'url' as a new content type in the application.
- Updated database queries to include copy count for snippets.
- Enhanced UI components to display copy count and handle URL snippets.

src/routes/+page.svelte

@@ -7,7 +7,7 @@
   import CenterPanel from '$lib/components/layout/CenterPanel.svelte';
   import RightPanel from '$lib/components/layout/RightPanel.svelte';
   import SettingsModal from '$lib/components/SettingsModal.svelte';
-  import type { CreateSnippetInput, UpdateSnippetInput, TimePeriod } from '$lib/types';
+  import type { CreateSnippetInput, UpdateSnippetInput, TimePeriod, ContentType } from '$lib/types';
 
   let mode = $state<'idle' | 'creating' | 'editing'>('idle');
   let formDirty = $state(false);
@@ -118,8 +118,9 @@
 
 <div class="app-layout">
   <LeftPanel
-    tags={store.tags}
+    tags={store.visibleTags}
     activeFilter={store.tagFilter}
+    contentTypeFilter={store.contentTypeFilter}
     timePeriodFilter={store.timePeriodFilter}
     onFilterChange={(tag) => {
       if (formDirty && !confirm('You have unsaved changes. Discard them?')) return;
@@ -127,6 +128,12 @@
       store.select(null);
       mode = 'idle';
     }}
+    onContentTypeChange={(ct: ContentType | null) => {
+      if (formDirty && !confirm('You have unsaved changes. Discard them?')) return;
+      store.setContentTypeFilter(ct);
+      store.select(null);
+      mode = 'idle';
+    }}
     onTimePeriodChange={(period: TimePeriod | null) => {
       if (formDirty && !confirm('You have unsaved changes. Discard them?')) return;
       store.setTimePeriodFilter(period);
@@ -142,6 +149,7 @@
     loading={store.loading}
     searchQuery={store.searchQuery}
     tagFilter={store.tagFilter}
+    contentTypeFilter={store.contentTypeFilter}
     timePeriodFilter={store.timePeriodFilter}
     onSelect={handleSelectSnippet}
     onSearch={(q) => {
@@ -170,7 +178,7 @@
 <style>
   .app-layout {
     display: grid;
-    grid-template-columns: 220px 1fr 360px;
+    grid-template-columns: 270px 1fr 360px;
     grid-template-rows: 100vh;
     height: 100vh;
     overflow: hidden;

src/routes/quicknote/+page.svelte

@@ -97,7 +97,7 @@
     <div class="field">
       <label for="type-buttons">Type</label>
       <div class="type-buttons" id="type-buttons" role="group">
-        {#each (['code', 'cli', 'text'] as ContentType[]) as t (t)}
+        {#each (['code', 'cli', 'text', 'url'] as ContentType[]) as t (t)}
           <button
             class="type-btn"
             class:active={contentType === t}