refactor(workspace): match KnowledgeView mini-chat dock style

- Widget is now a bottom-anchored dock spanning the content width
  (max-width 1200px, rounded top corners, bg-secondary, upward shadow)
  instead of a floating corner box.
- Drop the closed state and ✕ button — widget is always present,
  matching KnowledgeView's pattern. Collapsed = input-only dock,
  expanded = full ChatPanel above the input.
- Grid ratio 1fr:2fr → 0.85fr:2.15fr so tasks get a touch less room
  and notes a touch more.
- Workspace note-rail (the notes picker column inside the editor)
  widens from 155px to 200px so note titles breathe.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/components/WorkspaceChatWidget.vue

@@ -49,7 +49,7 @@ watch(
   }
 );
 
-type WidgetState = 'closed' | 'collapsed' | 'expanded';
+type WidgetState = 'collapsed' | 'expanded';
 const widgetState = ref<WidgetState>('collapsed');
 
 const chatPanelRef = ref<InstanceType<typeof ChatPanel> | null>(null);
@@ -89,7 +89,6 @@ function _storageKey(pid: number) {
   return `workspace_conv_${pid}`;
 }
 
-function open() { widgetState.value = 'collapsed'; }
 function expand() {
   widgetState.value = 'expanded';
   nextTick(() => chatPanelRef.value?.focus());
@@ -98,7 +97,6 @@ function collapse() {
   widgetState.value = 'collapsed';
   nextTick(() => inputBarRef.value?.focus());
 }
-function close() { widgetState.value = 'closed'; }
 
 async function restart() {
   const conv = await chatStore.createConversation();
@@ -166,19 +164,8 @@ defineExpose({ prefill });
 </script>
 
 <template>
-  <!-- Closed: small floating handle -->
-  <button
-    v-if="widgetState === 'closed'"
-    class="ws-chat-handle"
-    title="Open project chat"
-    @click="open"
-  >
-    💬 Chat
-  </button>
-
-  <!-- Collapsed or expanded: floating panel -->
+  <!-- Bottom-anchored chat dock: collapsed (input only) or expanded (full panel) -->
   <div
-    v-else
     class="ws-chat-widget"
     :class="{ 'ws-chat-widget--expanded': widgetState === 'expanded' }"
   >
@@ -214,7 +201,6 @@ defineExpose({ prefill });
             <polyline points="6 9 12 15 18 9"/>
           </svg>
         </button>
-        <button class="btn-icon-sm" title="Close chat" @click="close">✕</button>
       </div>
     </div>
 
@@ -248,51 +234,32 @@ defineExpose({ prefill });
 </template>
 
 <style scoped>
-.ws-chat-handle {
-  position: absolute;
-  right: 1rem;
-  bottom: 1rem;
-  z-index: 20;
-  padding: 0.5rem 0.9rem;
-  border-radius: 999px;
-  border: 1px solid var(--color-border);
-  background: var(--color-surface);
-  color: var(--color-text);
-  cursor: pointer;
-  font-size: 0.82rem;
-  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
-}
-.ws-chat-handle:hover {
-  border-color: var(--color-primary);
-  color: var(--color-primary);
-}
-
 .ws-chat-widget {
   position: absolute;
-  right: 1rem;
-  bottom: 1rem;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  max-width: var(--page-max-width);
+  margin-inline: auto;
   z-index: 20;
-  width: 380px;
   display: flex;
   flex-direction: column;
-  background: var(--color-surface);
-  border: 1px solid var(--color-border);
-  border-radius: 12px;
-  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
+  background: var(--color-bg-secondary);
+  border-radius: 16px 16px 0 0;
+  box-shadow: 0 -8px 32px rgba(0, 0, 0, 0.35), 0 -1px 0 rgba(255, 255, 255, 0.05);
   overflow: hidden;
-  transition: height 0.2s ease, width 0.2s ease;
+  transition: height 0.2s ease;
 }
 .ws-chat-widget--expanded {
-  width: 420px;
-  height: 560px;
+  height: 500px;
 }
 
 .ws-chat-header {
   display: flex;
   align-items: center;
   justify-content: space-between;
-  padding: 8px 12px;
-  border-bottom: 1px solid var(--color-border);
+  padding: 8px 14px;
+  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
   flex-shrink: 0;
 }
 .ws-chat-title {

frontend/src/components/WorkspaceNoteEditor.vue

@@ -457,7 +457,7 @@ defineExpose({ reload: loadProjectNotes });
 
 /* ── Left rail ── */
 .note-rail {
-  width: 155px;
+  width: 200px;
   flex-shrink: 0;
   display: flex;
   flex-direction: column;

frontend/src/views/WorkspaceView.vue

@@ -45,8 +45,8 @@ const panelOpen = ref<{ tasks: boolean; notes: boolean }>({ tasks: true, notes:
 
 const gridColumns = computed(() => {
   return [
-    panelOpen.value.tasks ? "minmax(0, 1fr)" : "0px",
-    panelOpen.value.notes ? "minmax(0, 2fr)" : "0px",
+    panelOpen.value.tasks ? "minmax(0, 0.85fr)" : "0px",
+    panelOpen.value.notes ? "minmax(0, 2.15fr)" : "0px",
   ].join(" ");
 });