feat(java): Add Project JDK and Maven home / settings.xml / local repository settings

The JDK was always picked automatically (JAVA_HOME, PATH, the usual install dirs, by the
module's Java version) and Maven was the project's mvnw or mvn on PATH, with no way to
override either. languages.java.jdk (Languages & Frameworks › Java › Project JDK) now sets
the default jdtls runtime, the JDK of Run/Debug and JAVA_HOME for Maven and Gradle;
languages.java.maven (Build Tools › Maven) sets the Maven home, -s and
-Dmaven.repo.local for sync, builds, tool-window goals and detected run configurations.
JDKs and Maven installations are detected for the pickers.

Closes #13

crates/ide-build/src/compile/mod.rs

@@ -225,6 +225,7 @@ fn maven_steps(root: &Path, model: &BuildModel, kind: BuildKind, module: Option<
     }
     let step = |p: &maven::MavenProject, extra: &[String]| {
         let mut s = BuildStep::new(&p.command, &["-B", "-Dstyle.color=never"], &subdir(root, &p.dir), Format::Maven);
+        s.args.extend(p.options.iter().cloned());
         s.args.extend(extra.iter().cloned());
         s.args.extend(goals.iter().map(|g| (*g).to_owned()));
         s.env = p.env.clone();

crates/ide-build/src/maven.rs

@@ -92,6 +92,8 @@ pub struct MavenProject {
     pub java_version: Option<u32>,
     /// Maven launcher: the nearest `mvnw` up to the project root (absolute), else `mvn`.
     pub command: String,
+    /// Options before the goals (`-s`, `-Dmaven.repo.local=`); filled in by the shell from settings.
+    pub options: Vec<String>,
     /// Environment for runs (`JAVA_HOME` of the matching JDK); filled in by the shell.
     pub env: BTreeMap<String, String>,
 }
@@ -924,6 +926,7 @@ pub(crate) fn load_with_repo(root: &Path, local_repo: Option<PathBuf>) -> MavenM
             profiles: pom.profiles.iter().map(|p| p.id.clone()).collect(),
             java_version: jv,
             command: wrapper(root, &dir),
+            options: Vec::new(),
             env: BTreeMap::new(),
         });
         for m in modules.into_iter().rev() {

crates/ide-build/src/sync.rs

@@ -29,6 +29,10 @@ pub struct SyncOptions {
     pub profiles: Vec<String>,
     /// Extra environment (`JAVA_HOME`).
     pub env: BTreeMap<String, String>,
+    /// Maven launcher replacing the project's `mvnw` / `mvn` (Settings › Maven home).
+    pub maven_command: Option<String>,
+    /// Maven options before the goals (`-s`, `-Dmaven.repo.local=`).
+    pub maven_options: Vec<String>,
 }
 
 #[derive(Clone, Debug, Default, Serialize, Deserialize)]
@@ -184,6 +188,7 @@ pub fn sync_maven(
         let effective = cache_dir.join(format!("effective-pom-{n}.xml"));
         let _ = std::fs::remove_file(&effective);
         let mut args: Vec<String> = vec!["-B".into(), "-fae".into(), "-Dstyle.color=never".into()];
+        args.extend(options.maven_options.iter().cloned());
         if options.offline {
             args.push("-o".into());
         }
@@ -194,7 +199,8 @@ pub fn sync_maven(
         args.push(format!("-Doutput={}", effective.to_string_lossy()));
         args.push("dependency:tree".into());
         progress(SyncProgress { message: format!("Reading {}", top.display_name), fraction: None });
-        let out = run(&top.command, &args, &root.join(&top.dir), &options.env, cancel, |line| {
+        let command = options.maven_command.as_deref().unwrap_or(&top.command);
+        let out = run(command, &args, &root.join(&top.dir), &options.env, cancel, |line| {
             if let Some((name, i, total)) = maven_building(line) {
                 let fraction = (i.saturating_sub(1) as f32 / total.max(1) as f32).min(1.0);
                 progress(SyncProgress { message: format!("Building model of {name}"), fraction: Some(fraction) });