MVP M1–M3: visual port, TipTap text editor, React Flow diagram

apps/web — Next.js 16 + TypeScript + React 19 (no Tailwind)

M1 Visual port
- Manuscript theme + base styles ported verbatim from design-source
- 100dvh layout with internal scroll regions (rail / narrative / dock thread)
- TopBar, LeftRail (collapsible sections + collapsed strip), CanvasHeader,
  StatusBar, EditorShell composing the dual-canvas
- SocratesDock (subtle/default/prominent) with bubbles + numbered options
- Sigil (Σ + laurel) used across editor and seed screens
- SeedScreen with emerging-seed rail, mini-graph, confidence bar, thread,
  typing indicator, input row
- Routes: / (homepage), /editor/[projectId], /seed
- Aristotle fixture in lib/fixtures (ported from data.js)

M2 Real text editor
- TipTap (StarterKit + custom Chip atom inline node + ReactNodeViewRenderer)
- Slash-menu insertion via @tiptap/suggestion with arrow / number-key shortcuts
- ChipFocusContext bridges narrative ↔ diagram hover/selection across the
  TipTap render boundary
- fixtureToDoc converts the fixture narrative → ProseMirror JSON

M3 Real diagram
- React Flow (@xyflow/react) custom node (block / actor / constraint / system)
  matching prototype's softened look
- Custom edge with bezier path + label renderer (association / composition /
  constraint variants)
- Drag-create from a left-side palette via HTML5 DnD + screenToFlowPosition
- NodeInspector panel: edit kind / label / properties (or expression for
  constraints); delete cascades to incident edges
- Bidirectional focus highlighting between chips (narrative) and blocks
  (diagram)
- Removed redundant legend (stereotype labels on nodes serve same purpose)

State for M3 lives in component memory; persistence + bidirectional sync land
in M4–M5.

apps/web/components/editor/TopBar.tsx

@@ -0,0 +1,36 @@
+// Top-level brand row: name + breadcrumbs on the left, sync pill + avatar on the right.
+// Ported from docs/design-source/socrata/project/editor-shell.jsx (TopBar).
+
+import type { FixtureData } from "../../lib/fixtures/aristotle";
+
+interface TopBarProps {
+  data: FixtureData;
+}
+
+export function TopBar({ data }: TopBarProps) {
+  return (
+    <header className="topbar">
+      <div className="topbar-left">
+        <div className="brand">
+          <span className="brand-name">Socrata</span>
+        </div>
+        <div className="breadcrumbs">
+          <span className="bc-sep">/</span>
+          <span className="bc-item">{data.project.scope}</span>
+          <span className="bc-sep">/</span>
+          <span className="bc-item bc-active">{data.project.name}</span>
+          <span className="bc-branch">
+            <span className="bc-branch-glyph">⎇</span> {data.project.branch}
+          </span>
+        </div>
+      </div>
+      <div className="topbar-right">
+        <div className="sync-pill">
+          <span className="sync-dot" /> model in sync · {data.project.lastSync}
+        </div>
+        <div className="topbar-divider" />
+        <div className="avatar">MC</div>
+      </div>
+    </header>
+  );
+}