feat: add jenv-gradle-low-ram skill for low-RAM Gradle builds

Author: wax911

.github/skills/jenv-gradle-low-ram/SKILL.md

@@ -0,0 +1,118 @@
+---
+name: jenv-gradle-low-ram
+description: 'Align jenv with .java-version and run Gradle reliably on low-RAM machines. Use for Java mismatch errors, Gradle OOMs, daemon memory pressure, and selecting safe build flags.'
+argument-hint: 'Describe your target task and available RAM, for example: assembleDebug on 8GB RAM'
+---
+# Jenv + Gradle Low-RAM Workflow
+
+## What This Skill Produces
+
+- A shell where `java` and Gradle use the Java version pinned by `.java-version`.
+- A repeatable Gradle command profile tuned for constrained memory.
+- Verification checks to confirm version alignment and build stability.
+
+## When To Use
+
+- Any time when `./gradlew` is about to be invoked in this repository.
+- Especially important for low-RAM machines where daemon/worker pressure can destabilize builds.
+- Required when verifying that Java from `.java-version` is the active runtime for Gradle.
+
+## Procedure
+
+1. Detect the required Java version.
+
+```bash
+cat .java-version
+```
+
+2. Verify `jenv` is installed and initialized.
+
+```bash
+command -v jenv
+jenv versions
+jenv version
+```
+
+Decision point:
+
+- If `jenv` is not found, install and initialize it in your shell startup.
+- If `jenv` is found but `jenv version` does not match `.java-version`, continue to step 3.
+
+3. Align local Java to the repository pin.
+
+```bash
+required_java="$(cat .java-version)"
+jenv local "$required_java"
+```
+
+Decision point:
+
+- If `jenv local` fails because the version is missing, install that JDK and run `jenv add <jdk-path>`, then retry.
+
+4. Confirm runtime alignment before any Gradle task.
+
+```bash
+java -version
+./gradlew -version
+```
+
+Quality check:
+
+- Gradle JVM version in `./gradlew -version` must match `.java-version` major version.
+
+5. Run Gradle with low-memory-safe defaults.
+
+Preferred one-off profile:
+
+```bash
+./gradlew --no-daemon --max-workers=2 \
+  -Dorg.gradle.jvmargs="-Xmx1536m -XX:MaxMetaspaceSize=512m -Dfile.encoding=UTF-8" \
+  assembleDebug
+```
+
+For tests:
+
+```bash
+./gradlew --no-daemon --max-workers=2 \
+  -Dorg.gradle.jvmargs="-Xmx1792m -XX:MaxMetaspaceSize=512m -Dfile.encoding=UTF-8" \
+  testDebugUnitTest
+```
+
+6. If memory pressure continues, downgrade concurrency.
+
+```bash
+./gradlew --no-daemon --max-workers=1 -Dorg.gradle.parallel=false assembleDebug
+```
+
+7. If builds are stable and you want persistence, prefer user-local Gradle overrides (avoid committing repo-wide memory changes).
+
+Suggested entries for `~/.gradle/gradle.properties`:
+
+```properties
+org.gradle.daemon=false
+org.gradle.parallel=false
+org.gradle.workers.max=2
+org.gradle.jvmargs=-Xmx1536m -XX:MaxMetaspaceSize=512m -Dfile.encoding=UTF-8
+```
+
+## Troubleshooting Branches
+
+- `jenv version` correct but `java -version` wrong:
+  Ensure shell init runs `eval "$(jenv init -)"` and enable export plugin with `jenv enable-plugin export`.
+- `Gradle daemon disappeared unexpectedly`:
+  Retry with `--no-daemon --max-workers=1` and lower `-Xmx` if the OS is reclaiming memory aggressively.
+- Kotlin compile OOM:
+  Keep workers low, disable parallel, and run module-targeted tasks (for example `:feature:media:assembleDebug`) instead of full-project builds.
+
+## Completion Checks
+
+- `.java-version` and `jenv version` resolve to the same Java release.
+- `./gradlew -version` reports the expected JVM.
+- Target Gradle task completes without OOM or daemon crash.
+- Machine remains responsive during build (no prolonged swap thrash).
+
+## Fast Invocation Examples
+
+- "Align my shell to `.java-version` and run debug build with 8GB RAM settings"
+- "I get class file major version errors; fix jenv and verify Gradle JVM"
+- "Run unit tests with a low-memory Gradle profile and fallback if OOM occurs"