fix(desktop): add duplicate-risk retry affordance

[WaldenLee2005]

Summary

Fixes agentenv/monorepo#776 by adding an explicit duplicate-risk acknowledgement path for uncertain outbound approval cards.

When an outbound action is in uncertain, the desktop card now:

• shows a distinct Confirm no duplicate & retry control alongside Cancel
• gates retry behind a confirmation dialog explaining the unknown-send/duplicate risk
• fetches the fresh action version with outbound_action_status
• re-executes with duplicate_risk_ack: true
• preserves existing sentinel handling for version mismatch, terminal actions, expiry, and duplicate-risk rejection

Nuance: the ack-retry affordance replaces the normal approve button only while the card is in uncertain, rather than adding a third button next to a disabled approve. This keeps the action explicit and visually distinct while avoiding a dead primary control.

Tests

• npm --prefix apps/puffer-desktop exec vitest run src/lib/api/desktop.workflow-daemon.test.ts
• npm --prefix apps/puffer-desktop exec vitest run src/lib/screens/agent/connectorDraftStatus.test.ts
• npm --prefix apps/puffer-desktop run check
• PUFFER_DESKTOP_TEST_PORT=1441 PUFFER_DESKTOP_USE_SYSTEM_CHROME=1 npm --prefix apps/puffer-desktop run test:desktop -- tests/outbound-gate-matrix.spec.ts