feat(modal): Add patch approval modal manager

- Create src/patch_modal.py with PatchModalManager class
- Manage patch approval workflow: request, apply, reject
- Provide singleton access via get_patch_modal_manager()
- Add 8 unit tests for modal manager

src/patch_modal.py

@@ -0,0 +1,73 @@
+from typing import Optional, Callable, List
+from dataclasses import dataclass, field
+
+@dataclass
+class PendingPatch:
+  patch_text: str
+  file_paths: List[str]
+  generated_by: str
+  timestamp: float
+
+class PatchModalManager:
+  def __init__(self):
+    self._pending_patch: Optional[PendingPatch] = None
+    self._show_modal: bool = False
+    self._on_apply_callback: Optional[Callable[[str], bool]] = None
+    self._on_reject_callback: Optional[Callable[[], None]] = None
+  
+  def request_patch_approval(self, patch_text: str, file_paths: List[str], generated_by: str = "Tier 4 QA") -> bool:
+    from time import time
+    self._pending_patch = PendingPatch(
+      patch_text=patch_text,
+      file_paths=file_paths,
+      generated_by=generated_by,
+      timestamp=time()
+    )
+    self._show_modal = True
+    return True
+  
+  def get_pending_patch(self) -> Optional[PendingPatch]:
+    return self._pending_patch
+  
+  def is_modal_shown(self) -> bool:
+    return self._show_modal
+  
+  def set_apply_callback(self, callback: Callable[[str], bool]) -> None:
+    self._on_apply_callback = callback
+  
+  def set_reject_callback(self, callback: Callable[[], None]) -> None:
+    self._on_reject_callback = callback
+  
+  def apply_patch(self, patch_text: str) -> bool:
+    if self._on_apply_callback:
+      return self._on_apply_callback(patch_text)
+    return False
+  
+  def reject_patch(self) -> None:
+    self._pending_patch = None
+    self._show_modal = False
+    if self._on_reject_callback:
+      self._on_reject_callback()
+  
+  def close_modal(self) -> None:
+    self._show_modal = False
+  
+  def reset(self) -> None:
+    self._pending_patch = None
+    self._show_modal = False
+    self._on_apply_callback = None
+    self._on_reject_callback = None
+
+_patch_modal_manager: Optional[PatchModalManager] = None
+
+def get_patch_modal_manager() -> PatchModalManager:
+  global _patch_modal_manager
+  if _patch_modal_manager is None:
+    _patch_modal_manager = PatchModalManager()
+  return _patch_modal_manager
+
+def reset_patch_modal_manager() -> None:
+  global _patch_modal_manager
+  if _patch_modal_manager:
+    _patch_modal_manager.reset()
+  _patch_modal_manager = None

tests/test_patch_modal.py

@@ -0,0 +1,89 @@
+import pytest
+from src.patch_modal import (
+  PatchModalManager, PendingPatch, 
+  get_patch_modal_manager, reset_patch_modal_manager
+)
+
+def test_patch_modal_manager_init():
+  manager = PatchModalManager()
+  assert manager.get_pending_patch() is None
+  assert manager.is_modal_shown() is False
+
+def test_request_patch_approval():
+  manager = PatchModalManager()
+  patch_text = "--- a/test.py\n+++ b/test.py\n@@ -1 +1 @@\n-old\n+new"
+  file_paths = ["test.py"]
+  
+  result = manager.request_patch_approval(patch_text, file_paths)
+  assert result is True
+  assert manager.is_modal_shown() is True
+  
+  pending = manager.get_pending_patch()
+  assert pending is not None
+  assert pending.patch_text == patch_text
+  assert pending.file_paths == file_paths
+
+def test_reject_patch():
+  manager = PatchModalManager()
+  manager.request_patch_approval("diff", ["file.py"])
+  
+  manager.reject_patch()
+  assert manager.get_pending_patch() is None
+  assert manager.is_modal_shown() is False
+
+def test_close_modal():
+  manager = PatchModalManager()
+  manager.request_patch_approval("diff", ["file.py"])
+  
+  manager.close_modal()
+  assert manager.is_modal_shown() is False
+
+def test_apply_callback():
+  manager = PatchModalManager()
+  called = []
+  
+  def apply_fn(patch: str) -> bool:
+    called.append(patch)
+    return True
+  
+  manager.set_apply_callback(apply_fn)
+  
+  patch_text = "--- a/test.py\n+++ b/test.py\n"
+  result = manager.apply_patch(patch_text)
+  
+  assert result is True
+  assert len(called) == 1
+  assert called[0] == patch_text
+
+def test_reject_callback():
+  manager = PatchModalManager()
+  called = []
+  
+  def reject_fn() -> None:
+    called.append(True)
+  
+  manager.set_reject_callback(reject_fn)
+  manager.reject_patch()
+  
+  assert len(called) == 1
+
+def test_reset():
+  manager = PatchModalManager()
+  manager.request_patch_approval("diff", ["file.py"])
+  manager.set_apply_callback(lambda x: True)
+  manager.set_reject_callback(lambda: None)
+  
+  manager.reset()
+  
+  assert manager.get_pending_patch() is None
+  assert manager.is_modal_shown() is False
+
+def test_get_patch_modal_manager_singleton():
+  reset_patch_modal_manager()
+  
+  mgr1 = get_patch_modal_manager()
+  mgr2 = get_patch_modal_manager()
+  
+  assert mgr1 is mgr2
+  
+  reset_patch_modal_manager()