Replace custom AndroidSignatureIgnore with standard @IgnoreJRERequirement

sqlite-jdbc's AndroidSignatureIgnore was a custom marker annotation
that only had meaning when their pom.xml configured the
animal-sniffer-maven-plugin with
<annotation>org.sqlite.util.AndroidSignatureIgnore</animation>. This
project does not configure animal-sniffer, so the vendored copy of
the annotation was inert.

Replaced with the standard @IgnoreJRERequirement from
org.codehaus.mojo:animal-sniffer-annotations 1.27 (latest stable).
The plugin recognises this annotation out of the box, so if signature
checking is ever enabled here it will work with zero further config.

Changes:

- pom.xml: add animal-sniffer-annotations 1.27, scope=provided
  (retention=CLASS, not needed at runtime).
- Delete src/main/java/net/ladenthin/llama/AndroidSignatureIgnore.java
- OSInfo.java:
  * Import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement.
  * Replace the three @AndroidSignatureIgnore(explanation = "Should
    not reach this code path") sites in isMusl, toRealPathOrEmpty,
    and isAlpineLinux with @IgnoreJRERequirement plus a one-line //
    comment preserving the explanation (the standard annotation has
    no explanation field).
  * Header lists this as a 4th documented deviation from upstream.

Verified:
- mvn clean compile: BUILD SUCCESS
- mvn test -Dtest=OSInfoTest,LlamaLoaderTest: 37/37 pass
- reuse lint: 137/137 files compliant with REUSE 3.3.

Author: claude

pom.xml

@@ -87,6 +87,15 @@ SPDX-License-Identifier: MIT
 			<version>1.5.32</version>
 			<scope>runtime</scope>
 		</dependency>
+		<!-- @IgnoreJRERequirement marker used by OSInfo (vendored from xerial/sqlite-jdbc)
+		     on a few methods that touch APIs unavailable on Android. Retention=CLASS, so
+		     the dep is compile-only (provided scope). -->
+		<dependency>
+			<groupId>org.codehaus.mojo</groupId>
+			<artifactId>animal-sniffer-annotations</artifactId>
+			<version>1.27</version>
+			<scope>provided</scope>
+		</dependency>
 	</dependencies>
 
 	<build>

src/main/java/net/ladenthin/llama/AndroidSignatureIgnore.java

@@ -31,6 +31,12 @@
 //      wrapper)  ->  org.slf4j.Logger / org.slf4j.LoggerFactory
 //      and drop the Supplier<String> lazy form (the two messages
 //      are constant strings, so eager construction is free).
+//   4. @AndroidSignatureIgnore(explanation = "...") (sqlite-jdbc's
+//      custom marker for animal-sniffer-maven-plugin)
+//      ->  @IgnoreJRERequirement from
+//      org.codehaus.mojo:animal-sniffer-annotations. The standard
+//      marker has no explanation field; the original strings are
+//      preserved as adjacent // comments.
 // The original Apache-2.0 copyright header from the upstream file is
 // preserved verbatim below.
 
@@ -69,6 +75,7 @@
 import java.util.Locale;
 import java.util.stream.Stream;
 
+import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -183,7 +190,8 @@ public static boolean isAndroidTermux() {
         }
     }
 
-    @AndroidSignatureIgnore(explanation = "Should not reach this code path")
+    // Should not reach this code path on Android.
+    @IgnoreJRERequirement
     public static boolean isMusl() {
         Path mapFilesDir = Paths.get("/proc/self/map_files");
         try (Stream<Path> dirStream = Files.list(mapFilesDir)) {
@@ -197,7 +205,8 @@ public static boolean isMusl() {
         }
     }
 
-    @AndroidSignatureIgnore(explanation = "Should not reach this code path")
+    // Should not reach this code path on Android.
+    @IgnoreJRERequirement
     private static String toRealPathOrEmpty(Path path) {
         try {
             return path.toRealPath().toString();
@@ -206,7 +215,8 @@ private static String toRealPathOrEmpty(Path path) {
         }
     }
 
-    @AndroidSignatureIgnore(explanation = "Should not reach this code path")
+    // Should not reach this code path on Android.
+    @IgnoreJRERequirement
     private static boolean isAlpineLinux() {
         try (Stream<String> osLines = Files.lines(Paths.get("/etc/os-release"))) {
             return osLines.anyMatch(l -> l.startsWith("ID") && l.contains("alpine"));