BOLT-1322 [2/7] packages/event-bus: extend CommandExecutedEvent with optional output field

Add optional 'output' field to CommandExecutedEvent so the OEM adapter can carry per-command result payload back to the device domain. Files (verify exact paths in packages/event-bus/src/events/command/): 1. Find the CommandExecutedEvent zod schema (likely under packages/event-bus/src/events/command/). Add 'output: z.unknown().optional()' (or 'z.record(z.unknown()).optional()'). 2. Update the TypeScript type export to include the optional field. 3. Update any version constants if the schema is versioned (e.g. 1.0.0 → 1.1.0). Optional fields are typically backwards compatible; double-check the repo convention before bumping major. 4. Unit tests: parse with output present, parse without output (existing producers must keep working). 5. Confirm downstream consumers (domains/device command.executed handler, adapters/oem/src/common/commandObservability, any analytics consumers) compile cleanly with the optional field. Branch: havoc/bolt-1322-event-bus Worktree: ../mono-bolt-1322-event-bus Depends on: none structurally, but [1/7] should land first for ergonomic typing. Done when: schema accepts and rejects correctly, type is exported, all event-bus tests pass.