Add the single authoritative tool-execution path (executeTool) plus the two
universal interfaces over it (design.md §2.5, §7.3):
- dispatch.ts: scope enforcement, ajv input validation, rate limiting, finance
egress redaction (redactDeep), and structured audit emission on one path.
- audit.ts / rate-limit.ts: injected AuditLogger + RateLimiter abstractions.
- mcp.ts: low-level MCP Server with scope-filtered tools/list (tool-hiding) and
tools/call routed through executeTool.
- http.ts: Express host mounting /mcp, /openapi.json, POST /tools/:name, /healthz.
- openapi.ts: buildOpenApiDocument wraps the existing path generator into a full
OpenAPI 3.1 document.
- local-auth.ts: LocalAuthProvider (dev bearer tokens) that refuses to construct
outside SH_MCP_ENV=local and enforces audience binding (design.md §3, §6).
