refactor: explicit returns + void floating promises (T3.a typeaware sweep) (#756)

Cluster T3.a — mechanical fixes for consistent-return and no-floating-promises.

Files touched (15):
- server/shared/tool-call-display.ts — default throw in buildCanonicalDetailDisplay switch
- server/agent/prompt-attachments.ts — default throw in renderPromptAttachmentAsText switch
- server/workspace-directory.ts — default throw in getSortValue switch
- server/agent/mcp-server.ts — default throw in mcpCreateWorktreeInput switch
- server/terminal/terminal-session-controller.ts — default return in dispatch switch
- server/daemon-e2e/agent-configs.ts — default return false in isProviderAvailable switch
- server/agent/agent-manager.ts — void dispatchSessionEvent fire-and-forget call
- server/agent/mcp-shared.ts — void 4 notify() floating calls
- app/agent-status-bar.utils.ts — default throw in getStatusSelectorHint switch
- app/keyboard-shortcuts.ts — default throw in resolvePayload switch
- app/resolve-agent-form.ts — default throw in resolveAgentForm switch
- app/ui/dropdown-menu.tsx — void .then() + return undefined for promise/always-return
- app/use-agent-form-state.ts — void refreshSnapshot() floating call
- cli/worktree/create.ts — default throw in toDaemonCreateInput switch
- cli/onboard.ts — return process.exit(1) to satisfy consistent-return in catch

Deferred (outside 15-file cap or in EXCLUDE list):
- server/worktree-session.ts — getSortValue (same pattern, cap reached)
- Multiple files with other errors (unbound-method, unsafe-type-assertion) are separate clusters

packages/server/src/server/agent/agent-manager.ts

@@ -1647,7 +1647,7 @@ export class AgentManager {
         { agentId, foregroundTurnId },
         "cancelAgentRun: foreground turn still active after timeout, force-canceling",
       );
-      this.dispatchSessionEvent(agent, {
+      void this.dispatchSessionEvent(agent, {
         type: "turn_canceled",
         provider: agent.provider,
         reason: "interrupted",

packages/server/src/server/agent/mcp-server.ts

@@ -2104,6 +2104,8 @@ function mcpCreateWorktreeInput(
       return {
         input: { ...base, action: "checkout", githubPrNumber: target.prNumber },
       };
+    default:
+      throw new Error("unreachable");
   }
 }
 

packages/server/src/server/agent/mcp-shared.ts

@@ -327,11 +327,11 @@ export function setupFinishNotification(params: SetupFinishNotificationParams):
           return;
         }
         if (event.agent.lifecycle === "error") {
-          notify("errored");
+          void notify("errored");
           return;
         }
         if (event.agent.lifecycle === "idle" && hasSeenRunning) {
-          notify("finished");
+          void notify("finished");
           return;
         }
         if (event.agent.lifecycle === "closed") {
@@ -343,7 +343,7 @@ export function setupFinishNotification(params: SetupFinishNotificationParams):
       }
 
       if (event.event.type === "permission_requested") {
-        notify("needs permission");
+        void notify("needs permission");
       }
     },
     { agentId: childAgentId, replayState: false },
@@ -362,7 +362,7 @@ export function setupFinishNotification(params: SetupFinishNotificationParams):
   if (childSnapshot.lifecycle === "running") {
     hasSeenRunning = true;
   } else if (childSnapshot.lifecycle === "error") {
-    notify("errored");
+    void notify("errored");
   }
 }
 

packages/server/src/server/agent/prompt-attachments.ts

@@ -54,6 +54,8 @@ export function renderPromptAttachmentAsText(attachment: AgentAttachment): strin
       });
       return lines.join("\n");
     }
+    default:
+      throw new Error("unreachable");
   }
 }
 

packages/server/src/server/daemon-e2e/agent-configs.ts

@@ -134,6 +134,8 @@ export function isProviderAvailable(provider: AgentProvider): Promise<boolean> {
             Boolean(process.env.OPENROUTER_API_KEY) ||
             existsSync(join(homedir(), ".pi", "agent", "auth.json")))
         );
+      default:
+        return false;
     }
   })();
 

packages/server/src/server/workspace-directory.ts

@@ -116,6 +116,8 @@ export class WorkspaceDirectory {
           return workspace.name.toLocaleLowerCase();
         case "project_id":
           return workspace.projectId.toLocaleLowerCase();
+        default:
+          throw new Error("unreachable");
       }
     },
   });

packages/server/src/shared/tool-call-display.ts

@@ -122,6 +122,8 @@ function buildCanonicalDetailDisplay(input: ToolCallDisplayInput): DetailDisplay
       };
     case "unknown":
       return {};
+    default:
+      throw new Error("unreachable");
   }
 }
 

packages/server/src/terminal/terminal-session-controller.ts

@@ -145,6 +145,8 @@ export class TerminalSessionController {
         return this.handleKillTerminalRequest(msg);
       case "capture_terminal_request":
         return this.handleCaptureTerminalRequest(msg);
+      default:
+        return undefined;
     }
   }