fix(prometheus): keep/drop patterns split on any whitespace, and a *_time_seconds value reads as a moment (#6423)

A pasted drop list whose line breaks had become spaces was stored as one
pattern that matched nothing, so Home Assistant's two 526-series
bookkeeping families filled the 1,000-series cap. No metric name holds
whitespace, so patterns now split on spaces and tabs as well as lines
and commas.

Home Assistant names its Unix times *_time_seconds (e.g.
homeassistant_last_updated_time_seconds), which read as "20751d 21h".
is_moment() takes both suffixes, for the value shown and the chart axis.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/prometheus/templates/prometheus/series.html

@@ -1,6 +1,7 @@
 {# plugins/prometheus/templates/prometheus/series.html — one stored series
    of a target (milestone 506): its newest value and a chart over a chosen
-   range. A *_timestamp_seconds series charts as moments, not numbers. #}
+   range. A moment series (*_timestamp_seconds, *_time_seconds) charts as
+   moments, not numbers. #}
 {% extends "base.html" %}
 {% from "_macros.html" import crumbs, page_header %}
 {% block title %}{{ metric }} — {{ target.name }} — Steward{% endblock %}