Add timeout + shielding to `NoBsWs` reconnect logic

Add timeout param to `.reset()` and `.send_msg()` to prevent
indefinite blocking on reconnect attempts. Shield reconnect
sleeps from cancellation to ensure we avoid any "finally footgun" type
scenarios where `trio.Cancelled` masks an underlying exc per,
- https://github.com/goodboy/tractor/pull/387
- https://github.com/goodboy/tractor/pull/391

Deats,
- add `timeout` param to `.reset()`, return `bool` for success
- add `timeout=3` default to `.send_msg()` for reconnect wait
- shield `.reset()` call in `.send_msg()` error handler
- log warning when reconnect timeout exceeded
- shield throttled sleeps in `_reconnect_forever()` error paths

(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code

piker/data/_web_bs.py

@@ -105,7 +105,10 @@ class NoBsWs:
     def connected(self) -> bool:
         return self._connected.is_set()
 
-    async def reset(self) -> None:
+    async def reset(
+        self,
+        timeout: float,
+    ) -> bool:
         '''
         Reset the underlying ws connection by cancelling
         the bg relay task and waiting for it to signal
@@ -114,18 +117,31 @@ class NoBsWs:
         '''
         self._connected = trio.Event()
         self._cs.cancel()
+        with trio.move_on_after(timeout) as cs:
             await self._connected.wait()
+            return True
+
+        assert cs.cancelled_caught
+        return False
 
     async def send_msg(
         self,
         data: Any,
+        timeout: float = 3,
     ) -> None:
         while True:
             try:
                 msg: Any = self._dumps(data)
                 return await self._ws.send_message(msg)
             except self.recon_errors:
-                await self.reset()
+                with trio.CancelScope(shield=True):
+                    reconnected: bool = await self.reset(
+                        timeout=timeout,
+                    )
+                    if not reconnected:
+                        log.warning(
+                            'Failed to reconnect after {timeout!r}s ??'
+                        )
 
     async def recv_msg(self) -> Any:
         msg: Any = await self._rx.receive()
@@ -191,7 +207,9 @@ async def _reconnect_forever(
                         f'{src_mod}\n'
                         f'{url} connection bail with:'
                     )
+                    with trio.CancelScope(shield=True):
                         await trio.sleep(0.5)
+
                     rent_cs.cancel()
 
                     # go back to reonnect loop in parent task
@@ -291,6 +309,7 @@ async def _reconnect_forever(
             log.exception(
                 'Reconnect-attempt failed ??\n'
             )
+            with trio.CancelScope(shield=True):
                 await trio.sleep(0.2)  # throttle
             raise berr