Multi-root workspace only initializes first folder

[mtarnovan]

First, thanks for this project, it's a great idea!

Description

In a multi-root VS Code/Cursor workspace, Dexter only initializes/indexes the first workspace folder. Files in additional folders are not treated as part of the active project root.

To reproduce

1. Create a workspace file like:

   {
     "folders": [
       { "path": "folder_a" },
       { "path": "folder_b" }
     ]
   }

2. Open that workspace in Cursor/VS Code.
3. Install/enable Dexter extension.
4. Open Elixir files from both folders.
5. Check Output → Dexter logs.

Actual behavior

Dexter initializes with only the first folder as root, e.g.:

• Dexter LSP v0.5.3 starting (root: /Users/.../folder_a)
• Initialize: projectRoot=/Users/.../folder_a debug=false
folder_b is not included as a root in this multi-folder workspace.

Expected behavior

Both workspace folders should be supported in multi-root mode, either by:

• running one LanguageClient per folder, or
• passing/handling all workspace folders correctly if single-server multi-root is intended.

Relevant code pointers

• Extension creates a single global client:
  https://github.com/remoteoss/dexter-vscode/blob/main/src/extension.ts#L8-L46
• Server initialize picks one root (WorkspaceFolders[0] / RootURI):
  https://github.com/remoteoss/dexter/blob/main/internal/lsp/server.go#L275-L287
• Server workspace-folder change handler is a no-op:
  https://github.com/remoteoss/dexter/blob/main/internal/lsp/server.go#L2006-L2008
• Server behavior is single projectRoot-scoped:
  • Indexing: https://github.com/remoteoss/dexter/blob/main/internal/lsp/server.go#L163-L199
  • Project-file guard: https://github.com/remoteoss/dexter/blob/main/internal/lsp/server.go#L485-L487
  • Formatting scope check: https://github.com/remoteoss/dexter/blob/main/internal/lsp/server.go#L2575-L2580
• VS Code language client init behavior when workspaceFolder is unset (workspaceFolders: null, rootPath from first folder):
  https://github.com/microsoft/vscode-languageserver-node/blob/release/client/9.0.1/client/src/common/client.ts#L1213-L1228

Docs context

The README section on .dexter.db root discovery appears to describe sub-app root recovery (e.g. Neovim rootUri in a monorepo), not true VS Code multi-root workspace support:
https://github.com/remoteoss/dexter/blob/main/README.md#index-database-location-dexterdb

Environment

• Dexter: 0.5.3
• Dexter VS Code extension: 0.2.1
• Editor: Cursor (likely reproducible in VS Code)
• OS: macOS

Workaround

Atm as a workaround I ran dexter init in the parent folder, which works but that has some unintended side effects, such as watchGitHead not working (since that expects a .git at the chosen root folder) + indexing stuff I don't need (all other sibling folders of folder_a and folder_b)

[JesseHerrick]

Hi @mtarnovan, thanks for the thorough writeup! It is correct that we don't support multi-root workspaces at the moment. However, I'd definitely love to add support at some point. Since this is not just a VS Code specific feature request, I'm going to move this issue to the main repo.