feat: progressive project tree view during import

[chagong]

Summary

Show Java project names in the JAVA PROJECTS tree view progressively as they are imported, instead of waiting for the entire import to complete. This reduces perceived loading time for large projects (e.g., 436 Gradle subprojects) from ~7 minutes to ~1 minute.

Problem

For large Gradle projects, the JDTLS import takes 6-7 minutes. During this time, the JAVA PROJECTS tree view is completely empty because:

1. serverReady() doesn't resolve until import completes
2. Even if we wait for serverRunning(), the server is blocked by Eclipse workspace locks and can't respond to queries like java.project.list

Solution

Instead of querying the server for project data, create tree nodes directly from ProjectsImported notification URIs sent progressively by JDTLS during import.

Key Changes

languageServerApiManager.ts

• Use serverRunning() (API >= 0.14) instead of serverReady() so the tree view can start rendering before import finishes
• Route onDidProjectsImport events to addProgressiveProjects() instead of refresh (which would query the blocked server)
• Route onDidClasspathUpdate during import to addProgressiveProjects() (non-destructive)
• After import completes (serverReady()), trigger full refresh to replace placeholders with real data
• Added isFullyReady() method

dependencyDataProvider.ts

• Added addProgressiveProjects() — creates ProjectNode items from URIs without server queries
• Guard getChildren() from entering getRootNodes() during progressive loading (prevents blocking on server queries that hang for the entire import)
• Keep TreeView progress spinner visible until first progressive items arrive via a deferred promise

commands.ts

• Added VIEW_PACKAGE_INTERNAL_ADD_PROJECTS command constant

Context

This is part of a 3-repo change for progressive project loading:

1. feat: progressive project import notifications for tree view eclipse-jdtls/eclipse.jdt.ls#3744 — Server-side progressive notifications
2. feat: add serverRunning() API (v0.14) for progressive loading redhat-developer/vscode-java#4372 — serverRunning() API (v0.14)
3. This PR — Client-side progressive tree view rendering

Testing

Tested with spring-boot project (436 Gradle subprojects):

• Before: Tree view empty for ~7 minutes until import completes
• After: 436 project names appear within ~1 minute of opening, with progress spinner showing until items arrive
• Works both with cached workspace (instant) and after "Clean Java Language Server Workspace" (progressive)
• After import completes, full refresh replaces placeholder items with proper expandable project nodes

[Copilot]

Pull request overview

Adds progressive population of the JAVA PROJECTS tree during JDTLS import by consuming ProjectsImported notifications, so users see project names earlier instead of waiting for full import completion.

Changes:

• Introduces progressive root project nodes in DependencyDataProvider and avoids root server queries while import is ongoing.
• Updates LanguageServerApiManager.ready() to use serverRunning() (when available) and wires import/classpath events to progressively add projects, followed by a full refresh after serverReady().
• Adds an internal command for progressively adding projects to the tree view.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 7 comments.

File	Description
src/views/dependencyDataProvider.ts	Adds progressive root node population and spinner/await logic during import.
src/languageServerApi/languageServerApiManager.ts	Switches readiness behavior to serverRunning() and routes JDTLS events to progressive updates + final refresh.
src/commands.ts	Adds internal command ID for progressive project insertion.
package-lock.json	Bumps package version metadata to 0.27.1.

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