fix: resolve agent only after workspace was resolved

Switched the order of the steps, the agent and hist state is resolved
only after the workspace was resolved and after it was in a running
state. Otherwise URI handling during workspace startup could provide
misleading errors related to agent not existing or not being ready.

src/main/kotlin/com/coder/toolbox/util/CoderProtocolHandler.kt

@@ -58,9 +58,11 @@ open class CoderProtocolHandler(
         val workspaceName = resolveWorkspaceName(params) ?: return
         val restClient = buildRestClient(deploymentURL, token) ?: return
         val workspace = restClient.workspaces().matchName(workspaceName, deploymentURL) ?: return
-        val agent = resolveAgent(params, workspace) ?: return
-
         if (!prepareWorkspace(workspace, restClient, workspaceName, deploymentURL)) return
+
+        // we resolve the agent after the workspace is started otherwise we can get misleading
+        // errors like: no agent available while workspace is starting or stopping
+        val agent = resolveAgent(params, workspace) ?: return
         if (!ensureAgentIsReady(workspace, agent)) return
 
         val cli = configureCli(deploymentURL, restClient)