Initial commit: Grounded Flutter frontend

A to-do app that doesn't believe you — an enforcement layer rather than a
neutral ledger.

Architecture ported from Autoreceptives/Frontend/Receptive: stacked MVVM with
the mandatory 4-file screen pattern, one ParentViewModel owning the loading /
network / error overlays and the handleError decision tree, one AppDataManager
gateway, dio comms carrying the three identity headers, secure storage with
random-suffixed keys, and a single-chokepoint Navigator. Package root and Dart
package name are both Grounded; org is nya.

The enforcement engine, one unit per formula in utils/:

- DebtEngine      w(class) x severity(d) x decay(t), sublinear severity so old
                  misses cannot swamp the score; abandonment 2x with 30-day
                  decay immunity; late complete retains 30%
- StandingEngine  Good -> Warned -> Grounded -> Lockdown, derived not set;
                  Grounded replaces home with the overdue queue
- CapacityEngine  blocks over-scheduling against p50 of historically completed
                  minutes, with a learned per-category estimation multiplier
- IntegrityEngine session integrity, weekly volume, plyometric contact ceiling
                  and enforced recovery gaps
- ExcuseAnalyser  on-device excuse clustering plus the confrontation copy
- GuardrailEngine distress detection and rationed amnesty
- ToneEngine      all enforcement copy, so the tone cap lives in one place

CommitmentEvent is append-only and is the source of truth rather than the
status field, which is what makes honest history and excuse analysis possible.

Goals contain commitments via parentId, and a task can be run from a
full-screen runner that derives elapsed time from wall-clock so screen-off
cannot lose time. Backgrounding pauses the clock and is counted. The runner is
mirrored into an ongoing notification, with alarm-class full-screen intents
reserved for non-negotiables.

Design language, fonts, icon and native splash are in place; Mason bricks are
retargeted to this project and verified end-to-end.

flutter analyze lib/ reports no errors.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Mfu2gQLSFN21YRBcU2NrTt

frontend/windows/runner/flutter_window.cpp

@@ -0,0 +1,71 @@
+#include "flutter_window.h"
+
+#include <optional>
+
+#include "flutter/generated_plugin_registrant.h"
+
+FlutterWindow::FlutterWindow(const flutter::DartProject& project)
+    : project_(project) {}
+
+FlutterWindow::~FlutterWindow() {}
+
+bool FlutterWindow::OnCreate() {
+  if (!Win32Window::OnCreate()) {
+    return false;
+  }
+
+  RECT frame = GetClientArea();
+
+  // The size here must match the window dimensions to avoid unnecessary surface
+  // creation / destruction in the startup path.
+  flutter_controller_ = std::make_unique<flutter::FlutterViewController>(
+      frame.right - frame.left, frame.bottom - frame.top, project_);
+  // Ensure that basic setup of the controller was successful.
+  if (!flutter_controller_->engine() || !flutter_controller_->view()) {
+    return false;
+  }
+  RegisterPlugins(flutter_controller_->engine());
+  SetChildContent(flutter_controller_->view()->GetNativeWindow());
+
+  flutter_controller_->engine()->SetNextFrameCallback([&]() {
+    this->Show();
+  });
+
+  // Flutter can complete the first frame before the "show window" callback is
+  // registered. The following call ensures a frame is pending to ensure the
+  // window is shown. It is a no-op if the first frame hasn't completed yet.
+  flutter_controller_->ForceRedraw();
+
+  return true;
+}
+
+void FlutterWindow::OnDestroy() {
+  if (flutter_controller_) {
+    flutter_controller_ = nullptr;
+  }
+
+  Win32Window::OnDestroy();
+}
+
+LRESULT
+FlutterWindow::MessageHandler(HWND hwnd, UINT const message,
+                              WPARAM const wparam,
+                              LPARAM const lparam) noexcept {
+  // Give Flutter, including plugins, an opportunity to handle window messages.
+  if (flutter_controller_) {
+    std::optional<LRESULT> result =
+        flutter_controller_->HandleTopLevelWindowProc(hwnd, message, wparam,
+                                                      lparam);
+    if (result) {
+      return *result;
+    }
+  }
+
+  switch (message) {
+    case WM_FONTCHANGE:
+      flutter_controller_->engine()->ReloadSystemFonts();
+      break;
+  }
+
+  return Win32Window::MessageHandler(hwnd, message, wparam, lparam);
+}