chore(mcp): add outputSchema to tools that lack it

[JSONbored]

Parent roadmap: #525
Parent phase: #544

Background

19 of the 29 MCP tools (preflight/score/agent tools 8, 13–16, 18–29) have no outputSchema, so MCP clients can't machine-validate their results. Pure non-visual hardening.

Goal

Add outputSchema to every MCP tool that lacks one.

Current Behavior

Only tools 1–6, 10, 11, 12, 17 have outputSchema (src/mcp/server.ts:278-368).

Desired Behavior

Each remaining tool gets a structured outputSchema mirroring the existing *OutputSchema pattern; package bin discovery stays consistent.

Implementation Requirements

• src/mcp/server.ts (+ package bin if it mirrors schemas). No behavior change to tool logic.

Public/Private Output Boundaries

• Schema only; no new output.

Acceptance Criteria

• All tools expose an outputSchema; mcp-discovery fixtures updated to assert it.

Testing Requirements

• npm run test:ci, 97%+ coverage. Extend test/unit/mcp-discovery.test.ts.