MCP `subscription_wake`: use a resting subscription again now, as the Subscriptions page's Wake button does, for a forge admin #5430

For: when the crew stalls because a Claude account is resting, the owner can wake it from a harness. subscriptionWake (POST /settings/subscriptions/:id/wake, src/http/server.ts:844) calls wakeSubscription (src/core/subscriptions.ts:385) and has no twin.

Done:

• [ ] A tool subscription_wake { id }, admin only (refused as the page refuses), runs the page's handler logic: an unknown id is the page's refusal, and a known one is woken with wakeSubscription. It answers { id, says }, with says worded as the page's flash.
• [ ] test/mcp-subscription-wake.test.ts covers three cases: a resting subscription is no longer resting after the call; an unknown id is refused; a non-admin is refused. Each fails without the tool.

Files: src/http/mcp.ts, docs/MCP.md, test/mcp-subscription-wake.test.ts.

• [ ] One row in docs/MCP.md, marked as a write in tools/list's annotations as the other writes are.
• [ ] Before pushing, run the new test, test/mcp.test.ts, test/mcp-docs.test.ts and test/mcp-size.test.ts. A red test elsewhere that main also has is named in the pull.

Risk: test/mcp-size.test.ts caps tools/list, so keep the description to one short sentence. #5418 (MCP subscriptions, the read) is separate and can land in either order. Never put a token in an answer.