fix: multiple platform handler bug fixes

- secrets.go: Log RowsAffected errors instead of silently discarding them
- a2a_proxy.go: Add 60s safety timeout to a2aClient HTTP client
- terminal.go: Fix defer ordering - always close WebSocket conn on error,
  only defer resp.Close() after successful exec attach
- webhooks.go: Add shortSHA() helper to safely handle empty HeadSHA

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

workspace-server/internal/handlers/a2a_proxy.go

@@ -87,7 +87,9 @@ const maxProxyResponseBody = 10 << 20
 // a2aClient is a shared HTTP client for proxying A2A requests to workspace agents.
 // No client-level timeout — timeouts are enforced per-request via context deadlines:
 // canvas = 5 min (Rule 3), agent-to-agent = 30 min (DoS cap).
-var a2aClient = &http.Client{}
+var a2aClient = &http.Client{
+	Timeout: 60 * time.Second, // Safety net for when context deadlines are missing
+}
 
 type proxyA2AError struct {
 	Status   int

workspace-server/internal/handlers/secrets.go

@@ -276,7 +276,10 @@ func (h *SecretsHandler) Delete(c *gin.Context) {
 		return
 	}
 
-	rows, _ := result.RowsAffected()
+	rows, err := result.RowsAffected()
+	if err != nil {
+		log.Printf("DeleteWorkspace: RowsAffected error: %v", err)
+	}
 	if rows == 0 {
 		c.JSON(http.StatusNotFound, gin.H{"error": "secret not found"})
 		return
@@ -418,7 +421,10 @@ func (h *SecretsHandler) DeleteGlobal(c *gin.Context) {
 		return
 	}
 
-	rows, _ := result.RowsAffected()
+	rows, err := result.RowsAffected()
+	if err != nil {
+		log.Printf("DeleteGlobal: RowsAffected error: %v", err)
+	}
 	if rows == 0 {
 		c.JSON(http.StatusNotFound, gin.H{"error": "secret not found"})
 		return

workspace-server/internal/handlers/terminal.go

@@ -97,7 +97,6 @@ func (h *TerminalHandler) HandleConnect(c *gin.Context) {
 		log.Printf("Terminal WebSocket upgrade error: %v", err)
 		return
 	}
-	defer conn.Close()
 
 	// No hard session deadline — terminal stays open as long as there is activity.
 	// The idle timeout (terminalSessionTimeout) resets on each keystroke in the
@@ -108,6 +107,7 @@ func (h *TerminalHandler) HandleConnect(c *gin.Context) {
 	// ContainerExecCreate succeeds even if the binary doesn't exist — the error
 	// only surfaces at attach/start time, so we must retry at the attach level.
 	var resp types.HijackedResponse
+	var execErr error
 	for _, shell := range []string{"/bin/bash", "/bin/sh"} {
 		execCfg := container.ExecOptions{
 			Cmd:          []string{shell},
@@ -118,20 +118,21 @@ func (h *TerminalHandler) HandleConnect(c *gin.Context) {
 		}
 		execID, createErr := h.docker.ContainerExecCreate(ctx, containerName, execCfg)
 		if createErr != nil {
-			err = createErr
+			execErr = createErr
 			continue
 		}
-		resp, err = h.docker.ContainerExecAttach(ctx, execID.ID, container.ExecAttachOptions{Tty: true})
-		if err == nil {
+		resp, execErr = h.docker.ContainerExecAttach(ctx, execID.ID, container.ExecAttachOptions{Tty: true})
+		if execErr == nil {
+			defer resp.Close()
 			break
 		}
 	}
-	if err != nil {
-		log.Printf("Terminal exec error: %v", err)
+	if execErr != nil {
+		log.Printf("Terminal exec error: %v", execErr)
 		conn.WriteMessage(websocket.TextMessage, []byte("Error: failed to create shell session\r\n"))
+		conn.Close()
 		return
 	}
-	defer resp.Close()
 
 	// Bridge: container stdout → WebSocket
 	done := make(chan struct{})

workspace-server/internal/handlers/webhooks.go

@@ -33,6 +33,15 @@ func NewWebhookHandlerWithWorkspace(workspaces *WorkspaceHandler) *WebhookHandle
 	}
 }
 
+// shortSHA returns the first n characters of a commit SHA, or the
+// full value if it's shorter than n. Safe for empty strings.
+func shortSHA(sha string) string {
+	if len(sha) < 7 {
+		return sha
+	}
+	return sha[:7]
+}
+
 // GitHub handles POST /webhooks/github/:id
 // It verifies X-Hub-Signature-256, maps supported events to A2A message/send,
 // then forwards through the same proxy flow used by /workspaces/:id/a2a.
@@ -266,7 +275,7 @@ func buildGitHubA2APayload(eventType, deliveryID string, rawBody []byte) (string
 			payload.WorkflowRun.RunNumber,
 			payload.WorkflowRun.Conclusion,
 			payload.WorkflowRun.HeadBranch,
-			payload.WorkflowRun.HeadSHA[:min(7, len(payload.WorkflowRun.HeadSHA))],
+			shortSHA(payload.WorkflowRun.HeadSHA),
 			payload.Sender.Login,
 			payload.WorkflowRun.Event,
 			payload.Repository.FullName,