Preserve preview harness, editor, email and task improvements

Snapshot current maintainer-preview application changes and regression fixtures for integration into lab. Excludes local runtime data, evaluation outputs and source backups. Focused Python regression selection: 140 passed; full suite not certified.

tests/test_browser_progress.py

@@ -0,0 +1,46 @@
+import json
+
+from src.clean_agent_preview import BrowserProgress, browser_observation_state
+
+
+def observation(text='heading "Building sets"', url='https://example.com', click=False):
+    value = json.dumps([{'result': {'snapshot': text, 'origin': url,
+                                  'lifecycle': {'timer': 123}}}])
+    return {'output': ('Done\n\n[post-click page state]\n' if click else '') + value}
+
+
+def test_repeated_noop_gets_guidance_without_disabling_browser():
+    progress = BrowserProgress()
+    assert not progress.observe({'action': 'open'}, observation())
+    action = {'action': 'click', 'target': '@e108'}
+    assert not progress.observe(action, observation(click=True))
+    assert 'remains available' in progress.observe(action, observation(click=True))
+    assert not progress.observe(action, observation(click=True))
+
+
+def test_repeat_click_that_changes_page_is_not_a_stall():
+    progress = BrowserProgress()
+    action = {'action': 'click', 'target': '@e10'}
+    for count in range(8):
+        assert not progress.observe(action, observation(f'Cart count {count}', click=True))
+
+
+def test_navigation_and_unknown_observation_reset_stall():
+    progress = BrowserProgress()
+    action = {'action': 'click', 'target': '@e10'}
+    progress.observe(action, observation())
+    progress.observe(action, observation())
+    assert not progress.observe(action, observation(url='https://example.com/new'))
+    assert not progress.observe(action, {'output': 'Done'})
+    assert not progress.observe(action, observation())
+
+
+def test_refs_only_changes_are_not_progress_and_truncation_is_unknown():
+    assert browser_observation_state(observation('button [ref=e1]')) == browser_observation_state(observation('button [ref=e52]'))
+    assert browser_observation_state({'output': '[{"result": [truncated]'}) is None
+
+
+def test_waits_and_observations_are_not_flagged_as_failed_actions():
+    progress = BrowserProgress()
+    for action in ['snapshot', 'wait', 'read', 'find'] * 3:
+        assert not progress.observe({'action': action}, observation())