Design and implement HTTP API runtime

[wauputr4]

Goal

Expose Wasila through an HTTP API after the CLI daemon stabilizes.

Scope

• Define API endpoints for customers, tickets, messages, owner summaries, and agent runs.
• Keep API compatible with existing SQLite and orchestration contracts.
• Add auth plan before serious use.

Acceptance Criteria

• External systems can integrate without shelling out to CLI.
• API docs describe endpoints and auth assumptions.
• API does not bypass storage, idempotency, or policy rules.