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.

src/email_reply_stream.py

@@ -0,0 +1,49 @@
+"""Stream only the explicitly delimited email body, never model reasoning."""
+import json
+import re
+
+
+def reply_body(raw, *, complete=False):
+    match = re.search(r'<<<\s*REPLY\s*>>>', raw, re.I)
+    if not match:
+        return ''
+    body = raw[match.end():]
+    end = re.search(r'<<<\s*END\s*>>>', body, re.I)
+    if complete and not end:
+        return ''
+    body = body[:end.start()] if end else body.split('<', 1)[0]
+    if re.search(r'</?think\b', body, re.I):
+        return ''
+    return body.strip()
+
+
+async def stream_reply(candidates, messages, emit, *, max_tokens=1536):
+    from src.llm_core import stream_llm
+    error = 'No usable reply returned'
+    for url, model, headers in candidates:
+        raw = ''
+        visible = ''
+        await emit({'type': 'reply', 'text': ''})
+        try:
+            async for chunk in stream_llm(url, model, messages, headers=headers,
+                    temperature=0.3, max_tokens=max_tokens, timeout=120, thinking_mode='off'):
+                for line in chunk.splitlines():
+                    if not line.startswith('data: ') or line[6:] == '[DONE]':
+                        continue
+                    event = json.loads(line[6:])
+                    if event.get('error'):
+                        raise RuntimeError(event['error'])
+                    if event.get('thinking'):
+                        continue
+                    raw += event.get('delta') or ''
+                    body = reply_body(raw)
+                    if body != visible:
+                        visible = body
+                        await emit({'type': 'reply', 'text': body})
+            if not reply_body(raw, complete=True):
+                raise ValueError('Model returned analysis or an incomplete reply, not a finished email')
+            return raw, model
+        except Exception as exc:
+            error = str(exc)
+            await emit({'type': 'reply', 'text': ''})
+    raise ValueError(error)