fix(staging): restore goAsync tracking in 5 dispatch calls + move config seeding pre-Start

Investigation of issue #1058 confirmed 3 regressions on staging (introduced
by the OFFSEC-003 promotion PR #1059):

1. workspace_dispatchers.go (4 calls): provisionWorkspaceAuto and
   RestartWorkspaceAutoOpts used bare `go func()` instead of
   `h.goAsync(func() { ... })`, losing goroutine WaitGroup tracking.
   Restored h.goAsync on all 4 dispatch sites.

2. a2a_proxy.go (1 call): resolveAgentURL used bare `go h.RestartByID()`
   when waking a hibernated workspace. Restored h.goAsync wrapper.

3. provisioner.go: config seeding (CopyTemplateToContainer +
   WriteFilesToContainer) was placed AFTER ContainerStart with warning-level
   errors. Moved before ContainerStart with hard error + container cleanup
   on failure. molecule-runtime reads /configs immediately on start; a
   post-Start copy races into FileNotFoundError crash loops.

All three changes are already present on main (PR #1041 cascade + later
main advances). This PR brings staging to parity.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

workspace-server/internal/handlers/a2a_proxy.go

@@ -645,7 +645,7 @@ func (h *WorkspaceHandler) resolveAgentURL(ctx context.Context, workspaceID stri
 			// the caller can retry once the workspace is back online (~10s).
 			if status == "hibernated" {
 				log.Printf("ProxyA2A: waking hibernated workspace %s", workspaceID)
-				go h.RestartByID(workspaceID)
+				h.goAsync(func() { h.RestartByID(workspaceID) })
 				return "", &proxyA2AError{
 					Status:  http.StatusServiceUnavailable,
 					Headers: map[string]string{"Retry-After": "15"},

workspace-server/internal/handlers/workspace_dispatchers.go

@@ -111,11 +111,11 @@ func (h *WorkspaceHandler) provisionWorkspaceAuto(workspaceID, templatePath stri
 		"sync":         false,
 	})
 	if h.cpProv != nil {
-		go h.provisionWorkspaceCP(workspaceID, templatePath, configFiles, payload)
+		h.goAsync(func() { h.provisionWorkspaceCP(workspaceID, templatePath, configFiles, payload) })
 		return true
 	}
 	if h.provisioner != nil {
-		go h.provisionWorkspace(workspaceID, templatePath, configFiles, payload)
+		h.goAsync(func() { h.provisionWorkspace(workspaceID, templatePath, configFiles, payload) })
 		return true
 	}
 	// No backend wired — mark failed so the workspace doesn't linger in
@@ -275,13 +275,13 @@ func (h *WorkspaceHandler) RestartWorkspaceAutoOpts(ctx context.Context, workspa
 	if h.cpProv != nil {
 		h.cpStopWithRetry(ctx, workspaceID, "RestartWorkspaceAuto")
 		// resetClaudeSession is Docker-only — CP has no session state to clear.
-		go h.provisionWorkspaceCP(workspaceID, templatePath, configFiles, payload)
+		h.goAsync(func() { h.provisionWorkspaceCP(workspaceID, templatePath, configFiles, payload) })
 		return true
 	}
 	if h.provisioner != nil {
 		// Docker.Stop has no retry — see docstring rationale.
 		h.provisioner.Stop(ctx, workspaceID)
-		go h.provisionWorkspaceOpts(workspaceID, templatePath, configFiles, payload, resetClaudeSession)
+		h.goAsync(func() { h.provisionWorkspaceOpts(workspaceID, templatePath, configFiles, payload, resetClaudeSession) })
 		return true
 	}
 	// No backend wired — same shape as provisionWorkspaceAuto's no-backend

workspace-server/internal/provisioner/provisioner.go

@@ -481,6 +481,22 @@ func (p *Provisioner) Start(ctx context.Context, cfg WorkspaceConfig) (string, e
 		return "", fmt.Errorf("failed to create container: %w", err)
 	}
 
+	// Seed /configs before the entrypoint starts. molecule-runtime reads
+	// /configs/config.yaml immediately; post-start copy races fast runtimes
+	// into a FileNotFoundError crash loop.
+	if cfg.TemplatePath != "" {
+		if err := p.CopyTemplateToContainer(ctx, resp.ID, cfg.TemplatePath); err != nil {
+			_ = p.cli.ContainerRemove(ctx, resp.ID, container.RemoveOptions{Force: true})
+			return "", fmt.Errorf("failed to copy template to container %s before start: %w", name, err)
+		}
+	}
+	if len(cfg.ConfigFiles) > 0 {
+		if err := p.WriteFilesToContainer(ctx, resp.ID, cfg.ConfigFiles); err != nil {
+			_ = p.cli.ContainerRemove(ctx, resp.ID, container.RemoveOptions{Force: true})
+			return "", fmt.Errorf("failed to write config files to container %s before start: %w", name, err)
+		}
+	}
+
 	if err := p.cli.ContainerStart(ctx, resp.ID, container.StartOptions{}); err != nil {
 		// Clean up created container on start failure
 		_ = p.cli.ContainerRemove(ctx, resp.ID, container.RemoveOptions{Force: true})
@@ -496,20 +512,6 @@ func (p *Provisioner) Start(ctx context.Context, cfg WorkspaceConfig) (string, e
 	// /configs and /workspace, then drops to agent via gosu). No per-start
 	// chown needed here.
 
-	// Copy template files into /configs if TemplatePath is set
-	if cfg.TemplatePath != "" {
-		if err := p.CopyTemplateToContainer(ctx, resp.ID, cfg.TemplatePath); err != nil {
-			log.Printf("Provisioner: warning — failed to copy template to container %s: %v", name, err)
-		}
-	}
-
-	// Write generated config files into /configs if ConfigFiles is set
-	if len(cfg.ConfigFiles) > 0 {
-		if err := p.WriteFilesToContainer(ctx, resp.ID, cfg.ConfigFiles); err != nil {
-			log.Printf("Provisioner: warning — failed to write config files to container %s: %v", name, err)
-		}
-	}
-
 	// Resolve the host-mapped port. Retry inspect up to 3 times if Docker hasn't
 	// bound the ephemeral port yet (rare race under heavy load).
 	hostURL := InternalURL(cfg.WorkspaceID) // fallback to Docker-internal