fix: DOC-1016: VS Code - Python Remote File Sourcing (#261)

I ran into some confusing issues while trying to document Python Remote
File Sourcing:
- VS Code was sometimes sourcing the .venv from a different workspace
when I was starting pip servers. I added logging so we can easily know
which Python interpreter is being used for Pip servers
- Managed server list did not always refresh when using the refresh
button in the treeview. I added a flag to force this

### Testing
- Open a workspace in VS Code (can be empty)
- Create a new Python .venv
- Install deephaven-server package in the .venv
   ```sh
    pip install deephaven-server
   ```
- In Deephaven view, if the "Managed" node doesn't show, click the
refresh button in the SERVERS treeview. It should show up
- In the `Output -> Deephaven Debug` panel, should see some entries for
`[PipServerController] DEBUG` showing the Python interpreter path for
the workspace
- Delete the Python `.venv` folder
- Refresh the treeview again. The "Managed" node should disappear

Author: bmingles

src/controllers/ExtensionController.ts

@@ -1031,7 +1031,7 @@ export class ExtensionController implements IDisposable {
   };
 
   onRefreshServerStatus = async (): Promise<void> => {
-    await this._pipServerController?.syncManagedServers();
+    await this._pipServerController?.syncManagedServers({ forceCheck: true });
     await this._serverManager?.updateStatus();
   };
 

src/controllers/PipServerController.ts

@@ -96,9 +96,12 @@ export class PipServerController implements IDisposable {
 
     const pythonInterpreterPath = await this.getPythonInterpreterPath();
     if (pythonInterpreterPath == null) {
+      logger.debug('Python interpreter path not found');
       return { isAvailable: false };
     }
 
+    logger.debug('Using Python interpreter:', pythonInterpreterPath);
+
     try {
       execFileSync(pythonInterpreterPath, ['-c', 'import deephaven_server']);
       return { isAvailable: true, interpreterPath: pythonInterpreterPath };
@@ -130,7 +133,7 @@ export class PipServerController implements IDisposable {
     }
 
     if (this._serverUrlTerminalMap.size > 0) {
-      await this.syncManagedServers(true);
+      await this.syncManagedServers({ preferExistingPsk: true });
 
       for (const port of this._serverUrlTerminalMap.keys()) {
         await this.pollUntilServerStarts(port);
@@ -323,12 +326,20 @@ export class PipServerController implements IDisposable {
 
   /**
    * Sync current managed server state with the server manager.
-   * @param preferExistingPsk If true, use existing PSK if one exists for each
+   * @param options Optional options:
+   *  - forceCheck If true, force a re-check of pip server availability
+   *  - preferExistingPsk If true, use existing PSK if one exists for each
    * server.
    * @returns
    */
-  syncManagedServers = async (preferExistingPsk = false): Promise<void> => {
-    if (!this._isPipServerInstalled) {
+  syncManagedServers = async ({
+    forceCheck = false,
+    preferExistingPsk = false,
+  }: {
+    forceCheck?: boolean;
+    preferExistingPsk?: boolean;
+  } = {}): Promise<void> => {
+    if (forceCheck || !this._isPipServerInstalled) {
       this._isPipServerInstalled = (await this.checkPipInstall()).isAvailable;
     }