DDSketch drops zero values; bump asap_sketchlib past #141

[GordonYuanyc]

data_plane pins asap_sketchlib 026cd18c, whose DDSketch ignores values ≤ 0. Two effects:

• Warm quantiles are computed over the positive values only. For a series with 80% zeros, p50 comes back 5.87; the exact value is 0.
• If any series is all zeros in the window, readout fails with DDS interpolated quantile is unavailable and the whole query is forwarded.

asap_sketchlib aa540b6 (#141) fixes this. It is not in a tag yet, but Cargo.lock already uses a later revision (a66fad6c) for asap-aware-mapping.

Ask: bump data_plane / asap-precompute-rs to ≥ aa540b6.