fix(lsp): skip widening for indexed source files (#2052)

Fixes #2034

Call hierarchy, Find Usages and rename widen a server's answer by opening project files that mention the symbol's name and asking again. For JDT LS those files are mostly sources it already analyses, so nearly every incoming-calls request ran a second, slow round before anything was shown. Widening now asks the server which candidates are already in its analysis scope (optional `openidea.workspace.coveredFiles` command, served by the bundled JDT extension using the live source search scope) and only opens the rest; a missing or failing answer keeps the previous behaviour. Covers call hierarchy, references and rename. Hierarchy on a multi-module Maven fixture: median 703 ms → 224 ms, one query round.

java/java-usages/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: OpenIDEA Java usages
 Bundle-SymbolicName: ai.openidea.usages;singleton:=true
-Bundle-Version: 1.8.0
+Bundle-Version: 1.9.0
 Bundle-RequiredExecutionEnvironment: JavaSE-21
 Require-Bundle: org.eclipse.jdt.ls.core,org.eclipse.jdt.core,
  org.eclipse.jdt.core.manipulation,org.eclipse.core.runtime,