Replace player-animation-lib with the Saturn emote library

- Every version depends on org.saturnclient:emotes-fabric
  (${emotes_version}+<mc>, bundled). playEmote plays Saturn's emotes
  through it, and sneaking stops your own emote and tells the server.
  Emotes now work on 1.21.6+ too, where player-animation-lib was
  commented out.
- Removed every player-animation-lib and bendy-lib reference: the KoSmX
  repository, the dependencies, the player_anim properties, and the old
  (partly commented out) code in SaturnProviderImpl and KeyInputHandler.
- Build: Loom 1.15 -> 1.17.21 (the emotes jar is built with 1.17 and
  older Loom refuses it), Gradle 9.3 -> 9.8 (needed by Loom 1.17), and
  sourceSets moved out of the dependencies block in the root build.gradle,
  which Gradle 9.8 rejects.
- common: points at the emote-library branch (saturnclientmc/common#5).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

gradlew

@@ -20,7 +20,7 @@
 
 ##############################################################################
 #
-#   Gradle start up script for POSIX generated by Gradle.
+#   gradlew start up script for POSIX generated by Gradle.
 #
 #   Important for running:
 #
@@ -29,7 +29,7 @@
 #       bash, then to run this script, type that shell name before the whole
 #       command line, like:
 #
-#           ksh Gradle
+#           ksh gradlew
 #
 #       Busybox and similar reduced shells will NOT work, because this script
 #       requires all of these POSIX shell features:
@@ -57,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/3d91ce3b8caaf77ad09f381f43615b715b53f72c/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.