fix: sshfs polling, WebSocket broadcast, prompt progress bar, resizable stats panel

- log_watcher: add --reopen-log mode (close/reopen each poll) for sshfs/network
  filesystems; fix nonlocal clients bug causing UnboundLocalError on first broadcast;
  fix list(clients) copy to prevent RuntimeError on concurrent set mutation
- log_parser: capture progress=X.XX from prompt timing lines into Metrics.prompt_progress
- frontend: show progress bar during processing_prompt state with PROMPT N% label;
  widen stats panel to 300px; remove model name truncation; add drag handle on
  right border of stats panel to resize between 280px–840px

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

log_watcher.py

@@ -15,11 +15,13 @@ class LogWatcher:
         on_line: Callable[[str], Awaitable[None]],
         on_offline: Optional[Callable[[], Awaitable[None]]] = None,
         offline_timeout: float = 60.0,
+        reopen: bool = False,
     ):
         self._path = Path(path)
         self._on_line = on_line
         self._on_offline = on_offline
         self._offline_timeout = offline_timeout
+        self._reopen = reopen
         self._task: Optional[asyncio.Task] = None
 
     def start(self) -> asyncio.Task:
@@ -33,6 +35,15 @@ class LogWatcher:
     async def _run(self):
         offline_since: Optional[float] = None
 
+        if self._reopen:
+            await self._run_reopen()
+        else:
+            await self._run_keepopen()
+
+    async def _run_keepopen(self):
+        """Default: keep file open and poll readline(). Works on local filesystems."""
+        offline_since: Optional[float] = None
+
         while True:
             try:
                 with open(self._path, 'r', errors='replace') as f:
@@ -54,7 +65,50 @@ class LogWatcher:
                     offline_since = now
                 elif now - offline_since >= self._offline_timeout and self._on_offline:
                     await self._on_offline()
-                    offline_since = None  # reset so we don't spam
+                    offline_since = None
+                await asyncio.sleep(min(self.FILE_RETRY_INTERVAL, self._offline_timeout))
+            except asyncio.CancelledError:
+                return
+
+    async def _run_reopen(self):
+        """Close and reopen each poll cycle. Use for network filesystems (e.g. sshfs)
+        that cache file content at open time and don't propagate remote appends to
+        held-open file descriptors."""
+        offline_since: Optional[float] = None
+        pos: int = -1  # -1 = not yet seeded
+
+        while True:
+            try:
+                with open(self._path, 'r', errors='replace') as f:
+                    f.seek(0, 2)
+                    end = f.tell()
+
+                    if pos < 0:
+                        f.seek(max(0, end - self.SEED_BYTES))
+                        if f.tell() > 0:
+                            f.readline()  # discard partial first line
+                        pos = f.tell()
+                    elif end < pos:
+                        pos = 0  # file truncated / rotated
+
+                    f.seek(pos)
+                    while True:
+                        line = f.readline()
+                        if line:
+                            pos = f.tell()
+                            await self._on_line(line)
+                        else:
+                            break
+
+                offline_since = None
+                await asyncio.sleep(self.POLL_INTERVAL)
+            except OSError:
+                now = asyncio.get_event_loop().time()
+                if offline_since is None:
+                    offline_since = now
+                elif now - offline_since >= self._offline_timeout and self._on_offline:
+                    await self._on_offline()
+                    offline_since = None
                 await asyncio.sleep(min(self.FILE_RETRY_INTERVAL, self._offline_timeout))
             except asyncio.CancelledError:
                 return