fix(frontend): drop dead resample trigger/resolutions config

config.ResampleConfig stopped emitting the trigger and resolutions fields,
but MetricPlot still read them. resampleResolutions and resampleMinimum
were therefore always null, which made the array-based resolution branch in
the setScale hook unreachable and the timestep !== resampleMinimum guard
always true. Keep only the policy-based branch and derive the zoom trigger
straight from targetPoints.

configs/config-large.json still carried the removed minimum-points, trigger
and resolutions keys, which DisallowUnknownFields now rejects, so starting
against it aborted. Replace them with the current keys and add a test that
loads the file, so the example configs cannot drift out of the schema
unnoticed again.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

web/web.go

@@ -294,7 +294,7 @@ type Page struct {
 	FilterPresets map[string]any         // For pages with the Filter component, this can be used to set initial filters.
 	Infos         map[string]any         // For generic use (e.g. username for /monitoring/user/<id>, job id for /monitoring/job/<id>)
 	Config        map[string]any         // UI settings for the currently logged in user (e.g. line width, ...)
-	Resampling    *config.ResampleConfig // If not nil, defines resampling trigger and resolutions
+	Resampling    *config.ResampleConfig // If not nil, defines the target point count for zoom resampling
 	Redirect      string                 // The originally requested URL, for intermediate login handling
 	FooterLinks   FooterLinks            // Resolved legal links for the site footer
 }