Summary

Add support for $/progress notifications during workspace indexing to allow LSP clients to display progress information to users.

Motivation

When opening a large Nextflow project, the language server takes significant time to index all .nf files before it can respond to requests like workspace/symbol or textDocument/documentSymbol. During this time, clients have no way to know:

1. That indexing is in progress
2. How far along the indexing is
3. When indexing will complete

This results in a poor user experience where the editor/client appears to be "stuck" or unresponsive.

Proposed Solution

Implement the LSP Progress support for workspace indexing:

1. Create a progress token during initialization using window/workDoneProgress/create
2. Send $/progress notifications during the update() method in LanguageService.java with:
   • kind: "begin" when starting to index
   • kind: "report" with percentage (0-100) and/or message (e.g., "Indexing file 15/60") as files are processed
   • kind: "end" when indexing completes

-> window/workDoneProgress/create { token: "indexing" }
<- $/progress { token: "indexing", value: { kind: "begin", title: "Indexing workspace", percentage: 0 } }
<- $/progress { token: "indexing", value: { kind: "report", percentage: 25, message: "15/60 files" } }
<- $/progress { token: "indexing", value: { kind: "report", percentage: 50, message: "30/60 files" } }
<- $/progress { token: "indexing", value: { kind: "report", percentage: 100, message: "60/60 files" } }
<- $/progress { token: "indexing", value: { kind: "end", message: "Indexed 60 files" } }

private void update0() {
    // ...
    var uris = fileCache.removeChangedFiles();
    if( !scanned ) {
        if( uris.isEmpty() ) {
            uris = getWorkspaceFiles();  // <-- We know the total count here
            // Could send begin progress here
        }
    }
    // ...
    var changedUris = astCache.update(uris, fileCache);
    // Could send progress updates during astCache.update()
}