Summary

• Implements Sage #214 Appendix C PR-0.1a as the first focused Ricky-generated slice.
• Adds the new @agent-assistant/persona workspace package with type-only persona contracts for executors, triggers, memory, delivery, and sandbox borrow config.
• Registers the package in the root workspace and lockfile.

Scope

• This PR is intentionally type-only.
• Validators, JSON schema generation, dispatch/runtime wiring, Sage/cloud/workforce integration, and persona manifests are deferred to follow-up PR-0.1b/0.1c slices.

Ricky execution notes

• Generated/executed via local Ricky against /private/tmp/sage-ricky-214-specs/pr-0.1a-agent-assistant-persona-types.md.
• Ricky produced the implementation and final review artifacts with NO_ISSUES_FOUND.
• Ricky runtime wrapper still reported UNSUPPORTED_RUNTIME after the foreground broker process was stopped from a post-review hang, and the generated validation gate failed to materialize the explicit spec commands. I therefore ran the exact spec validation manually after the Ricky run before pushing.

Validation

• npm install --ignore-scripts
• npm run -w @agent-assistant/persona build
• npm run -w @agent-assistant/persona test
• node -e "import('@agent-assistant/persona').then((m) => console.log(Object.keys(m).length))" -> 0
• git diff --check

No merge performed.