Just warn on single-bar nulls instead of bping

Replace the debug breakpoint with a warning-log when a single-bar
null-segment is detected in `get_null_segs()`. This lets the gap
analysis continue while still alerting about the anomaly.

Deats,
- extract the 3-bar window (before, null, after) and calculate
  a `gap: pendulum.Interval` for the warning msg.
- comment-out the old breakpoint block for optional debugging as needed.

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

piker/tsp/_anal.py

@@ -276,14 +276,41 @@ def get_null_segs(
         absi_zdiff: np.ndarray = np.diff(absi_zeros)
 
         if zero_t.size < 2:
-            try:
-                breakpoint()
-            except RuntimeError:
-                # XXX, if greenback not active from
-                # piker store ldshm cmd..
-                log.exception(
-                    "Can't debug single-sample null!\n"
+            idx: int = zero_t['index'][0]
+            idx_before: int = idx - 1
+            idx_after: int = idx + 1
+            index = frame['index']
+            before_cond = idx_before <= index
+            after_cond = index <= idx_after
+            bars: np.ndarray = frame[
+                before_cond
+                &
+                after_cond
+            ]
+            time: np.ndarray = bars['time']
+            from pendulum import (
+                from_timestamp,
+                Interval,
             )
+            gap: Interval = (
+                from_timestamp(time[-1])
+                -
+                from_timestamp(time[0])
+            )
+            log.warning(
+                f'Single OHLCV-bar null-segment detected??\n'
+                f'gap -> {gap}\n'
+            )
+
+            # ^^XXX, if you want to debug the above bar-gap^^
+            # try:
+            #     breakpoint()
+            # except RuntimeError:
+            #     # XXX, if greenback not active from
+            #     # piker store ldshm cmd..
+            #     log.exception(
+            #         "Can't debug single-sample null!\n"
+            #     )
 
             return None