feat(design): surface phase PR 5 — Project + Workspace polish

Per the surface-phase spec for the Project list, Project view, and
3-panel Workspace cluster:

Button reclassification per Hybrid rule
- ProjectView:
  - btn-workspace ("Open Workspace"): kept on accent gradient — the
    workspace is the project's central feature moment, a Scribe-
    flavored action, brand moment per the doc.
  - btn-share: muted-outline → Bronze action-secondary
  - btn-danger-outline (Delete project): generic-border + danger-on-
    hover → Oxblood outline + filled hover (proper destructive)
  - btn-save-panel: accent gradient → Moss action-primary
  - btn-ms-confirm (milestone confirm): flat accent → Moss
  - btn-ms-cancel: ghost → Bronze action-secondary
  - .modal-btn-danger: --color-danger → --color-action-destructive
- ProjectListView:
  - btn-primary ("+ New Project"): flat accent → Moss action-primary.
    Empty-state CTA (.empty-action) keeps accent — that *is* a
    brand moment per Hybrid, "create your first project".
- WorkspaceTaskPanel + WorkspaceNoteEditor:
  - btn-delete-task / btn-delete: hover --color-danger → Oxblood
  - btn-delete-confirm / btn-confirm-delete: --color-danger pair →
    --color-action-destructive pair, with filled hover for stronger
    affordance
  - btn-save (WorkspaceNoteEditor): flat accent → Moss
- WorkspaceChatWidget:
  - History toggle: replaced unicode ▾ with Lucide ChevronDown
    (PR 1 carry-over for emoji-as-icon)

Two-weights-only
- Snapped every font-weight 600/700 to 500 across the cluster.

Borders kept (per structural-not-decorative rule)
- Milestone group cards: standalone containers, keep
- Project cards in list: standalone containers, keep
- Task slide-over panel: drawer modal, keep
- Workspace 3-panel separators: major section dividers, keep

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

frontend/src/components/WorkspaceNoteEditor.vue

@@ -480,7 +480,7 @@ defineExpose({ reload: loadProjectNotes });
   text-transform: uppercase;
   letter-spacing: 0.04em;
   font-size: 0.72rem;
-  font-weight: 600;
+  font-weight: 500;
   flex: 1;
 }
 
@@ -631,18 +631,20 @@ defineExpose({ reload: loadProjectNotes });
   align-items: center;
 }
 .note-row:hover .btn-delete { opacity: 1; }
-.btn-delete:hover { color: var(--color-danger, #e74c3c); }
+.btn-delete:hover { color: var(--color-action-destructive); }
 
 .btn-confirm-delete {
   background: none;
-  border: 1px solid var(--color-danger, #e74c3c);
-  color: var(--color-danger, #e74c3c);
+  border: 1px solid var(--color-action-destructive);
+  color: var(--color-action-destructive);
   font-size: 0.65rem;
-  font-weight: 600;
+  font-weight: 500;
   cursor: pointer;
   padding: 0.1rem 0.3rem;
   border-radius: 3px;
+  transition: background 0.15s, color 0.15s;
 }
+.btn-confirm-delete:hover:not(:disabled) { background: var(--color-action-destructive); color: #fff; }
 .btn-confirm-delete:disabled { opacity: 0.5; cursor: default; }
 
 .btn-cancel-delete {
@@ -730,15 +732,18 @@ defineExpose({ reload: loadProjectNotes });
 .unsaved { font-size: 0.72rem; color: var(--color-text-muted); }
 .saving-txt { font-size: 0.72rem; color: var(--color-primary); }
 
+/* Moss action-primary per Hybrid */
 .btn-save {
-  background: var(--color-primary);
+  background: var(--color-action-primary);
   color: #fff;
   border: none;
   border-radius: 5px;
   padding: 0.25rem 0.7rem;
   font-size: 0.8rem;
   cursor: pointer;
+  transition: background 0.15s;
 }
+.btn-save:hover:not(:disabled) { background: var(--color-action-primary-hover); }
 .btn-save:disabled { opacity: 0.4; cursor: default; }
 
 .note-title-row {
@@ -751,7 +756,7 @@ defineExpose({ reload: loadProjectNotes });
   background: transparent;
   border: none;
   font-size: 1.4rem;
-  font-weight: 600;
+  font-weight: 500;
   line-height: 1.25;
   color: var(--color-text);
   padding: 0;
@@ -844,7 +849,7 @@ defineExpose({ reload: loadProjectNotes });
   font-size: 0.7rem;
   color: var(--color-text-muted);
   flex-shrink: 0;
-  font-weight: 600;
+  font-weight: 500;
   text-transform: uppercase;
   letter-spacing: 0.04em;
 }