refactor: deprecate login_before_ready in favor of startup_script_behavior (#7837)

Fixes #7758

coderd/apidoc/swagger.json

@@ -8312,7 +8312,7 @@
           "$ref": "#/definitions/codersdk.WorkspaceAgentLifecycle"
         },
         "login_before_ready": {
-          "description": "LoginBeforeReady if true, the agent will delay logins until it is ready (e.g. executing startup script has ended).",
+          "description": "Deprecated: Use StartupScriptBehavior instead.",
           "type": "boolean"
         },
         "name": {
@@ -8340,6 +8340,9 @@
         "startup_script": {
           "type": "string"
         },
+        "startup_script_behavior": {
+          "$ref": "#/definitions/codersdk.WorkspaceAgentStartupScriptBehavior"
+        },
         "startup_script_timeout_seconds": {
           "description": "StartupScriptTimeoutSeconds is the number of seconds to wait for the startup script to complete. If the script does not complete within this time, the agent lifecycle will be marked as start_timeout.",
           "type": "integer"
@@ -8461,6 +8464,14 @@
         }
       }
     },
+    "codersdk.WorkspaceAgentStartupScriptBehavior": {
+      "type": "string",
+      "enum": ["blocking", "non-blocking"],
+      "x-enum-varnames": [
+        "WorkspaceAgentStartupScriptBehaviorBlocking",
+        "WorkspaceAgentStartupScriptBehaviorNonBlocking"
+      ]
+    },
     "codersdk.WorkspaceAgentStatus": {
       "type": "string",
       "enum": ["connecting", "connected", "disconnected", "timeout"],