feat: shared supervisor timeline, story assignment and time-spiral view

Each source version is extracted once for every review scope; events carry spans and projects from their sources, and attention density is counted from messages. After publication, events are assigned to project features and sub-threads (cross-project stories only when enabled), with user rename, merge, remove, move and undo. The story graph gains a lazily loaded Three.js time-spiral view. Includes the 3D concept demo, real-data DeepSeek check scripts and docs.

package.json

@@ -378,6 +378,7 @@
     "@types/react": "^19.2.17",
     "@types/react-dom": "^19.2.3",
     "@types/ssh2": "^1.15.5",
+    "@types/three": "^0.186.0",
     "@vitejs/plugin-react": "^5.2.0",
     "@xterm/addon-fit": "0.11.0",
     "@xterm/addon-search": "0.16.0",
@@ -408,6 +409,7 @@
     "remark-gfm": "^4.0.1",
     "remark-math": "^6.0.0",
     "tar": "7.5.22",
+    "three": "^0.186.1",
     "typescript": "^6.0.3",
     "typescript-eslint": "^8.65.0",
     "vite": "^7.3.6",