refactor: establish shared frontend shell

docs/governance/architecture-inventory.json

@@ -254,8 +254,8 @@
   "code_hotspots": [
     {
       "path": "static/app.js",
-      "bytes": 447568,
-      "lines": 9403
+      "bytes": 441609,
+      "lines": 9262
     },
     {
       "path": "static/styles.css",
@@ -274,8 +274,8 @@
     },
     {
       "path": "static/index.html",
-      "bytes": 133691,
-      "lines": 1873
+      "bytes": 133815,
+      "lines": 1875
     },
     {
       "path": "database.py",

docs/governance/stage-15-frontend-shell.md

@@ -0,0 +1,42 @@
+# Stage 15: Shared Frontend Shell and Page Registry
+
+## Runtime Page Registry
+
+`static/pages.config.js` is the build-free runtime representation of
+`config/pages.config.json`. It registers every primary workspace plus the internal strategy
+tracking workspace. Automated parity checks prevent titles, feature ownership, access labels,
+groups, default-page selection, and layout metadata from drifting between the two registries.
+
+Legacy route aliases are resolved by the registry instead of page business code. The registry
+describes navigation and presentation metadata only; backend authorization remains
+authoritative.
+
+## Shared Shell
+
+`static/shared/shell.js` now owns:
+
+- sidebar initialization, persistence, collapse state, and responsive control labels;
+- primary and mobile navigation binding and active-state synchronization;
+- workspace mounting, entry animation, URL state, and scroll reset;
+- header command-menu lifecycle;
+- market-summary expansion;
+- status-bar page titles and data dates;
+- the single-open-dialog lifecycle used by global application dialogs.
+
+`static/app.js` retains feature-specific enter and leave behavior, such as stopping Wentian
+animations or loading auction data. It asks the shell to mount a registered page and no longer
+mutates global page geometry directly.
+
+## Compatibility
+
+- Existing DOM IDs, CSS classes, query parameters, page animations, and mobile navigation are
+  unchanged.
+- `screenerTrackingView` continues to highlight the Intelligent Screener navigation item.
+- Existing function entry points remain as thin compatibility facades where feature code still
+  calls status, dialog, or command-menu services.
+
+## Residual Risk
+
+Feature renderers and feature event binding still share `static/app.js`. Their state ownership
+is now explicit and their shell dependencies are removed, so later page-module extraction can
+be performed one feature at a time instead of as a single rewrite.