feat(coderd/database): add task status and status view (#20235)

This change updates the `task_workspace_apps` table structure for
improved linking to workspace builds and adds queries to manage tasks
and a view to expose task status.

Updates coder/internal#948
Supersedes coder/coder#20212
Supersedes coder/coder#19773

coderd/database/unique_constraint.go

@@ -59,6 +59,7 @@ const (
 	UniqueTailnetCoordinatorsPkey                             UniqueConstraint = "tailnet_coordinators_pkey"                                       // ALTER TABLE ONLY tailnet_coordinators ADD CONSTRAINT tailnet_coordinators_pkey PRIMARY KEY (id);
 	UniqueTailnetPeersPkey                                    UniqueConstraint = "tailnet_peers_pkey"                                              // ALTER TABLE ONLY tailnet_peers ADD CONSTRAINT tailnet_peers_pkey PRIMARY KEY (id, coordinator_id);
 	UniqueTailnetTunnelsPkey                                  UniqueConstraint = "tailnet_tunnels_pkey"                                            // ALTER TABLE ONLY tailnet_tunnels ADD CONSTRAINT tailnet_tunnels_pkey PRIMARY KEY (coordinator_id, src_id, dst_id);
+	UniqueTaskWorkspaceAppsPkey                               UniqueConstraint = "task_workspace_apps_pkey"                                        // ALTER TABLE ONLY task_workspace_apps ADD CONSTRAINT task_workspace_apps_pkey PRIMARY KEY (task_id, workspace_build_number);
 	UniqueTasksPkey                                           UniqueConstraint = "tasks_pkey"                                                      // ALTER TABLE ONLY tasks ADD CONSTRAINT tasks_pkey PRIMARY KEY (id);
 	UniqueTelemetryItemsPkey                                  UniqueConstraint = "telemetry_items_pkey"                                            // ALTER TABLE ONLY telemetry_items ADD CONSTRAINT telemetry_items_pkey PRIMARY KEY (key);
 	UniqueTemplateUsageStatsPkey                              UniqueConstraint = "template_usage_stats_pkey"                                       // ALTER TABLE ONLY template_usage_stats ADD CONSTRAINT template_usage_stats_pkey PRIMARY KEY (start_time, template_id, user_id);