Mark the logs that carry a failure line on the artifact index

The artifact index listed the stored logs as bare file names, so a red build
gave no hint which of build.log, build.stdout.log and build.stderr.log actually
explains it — with stdout and stderr stored separately, the failure is usually
in only some of them.

Each log of a non-green build is now scanned for an upper-case FAILED/FAILURE,
which covers BUILD FAILED, Maven's BUILD FAILURE and Gradle's per-test
"SomeTest > works() FAILED"; lower-case prose does not count. The scan streams
line by line with an early exit and reads ISO-8859-1, so no byte sequence of a
build log can fail to decode. Logs of a successful build are not scanned at all
— that saves reading megabytes per page view and avoids an alarming badge on a
green build whose log mentions a deliberately failing sub-build.

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

build.gradle.kts

@@ -9,8 +9,9 @@ plugins {
 }
 
 group = "de.hoennig"
-// bump at least the patch version for every deployment, so the UI footer
-// (BuildProperties) and --version identify what is actually running
+// bump at least the patch version for every deployment — and only then, not per commit —
+// so the UI footer (BuildProperties), --version and the release notes identify what is
+// actually running; a deployment bundles whatever was committed since the last one
 version = "0.9.10"
 
 java {