Tooling: agent-driven fileFutureIdea tool that posts to fork issues

[heavygee]

Problem

Operator and agents frequently spawn "future ideas" mid-conversation. Right now those ideas evaporate unless someone manually drafts a plan doc or files an issue (this very issue is one of fourteen filed in one session because the operator dumped a batch).

Proposal

Give the agent a first-class "log a future idea" tool that:

1. Accepts a title + body
2. Files an issue on the local fork repo (heavygee/hapi -- never upstream tiann/hapi)
3. Labels it future-idea (new label, needs creating)
4. Optionally links to the originating session id

Tool surface:

fileFutureIdea({
  title: string,
  body: string,
  links?: { sessionId?: string, refIssue?: number },
  labels?: string[],
})

Authority model:

• Default off; operator enables per-session via a settings flag or per-call with explicit consent.
• Agent must surface the proposed title + body in the response and require operator approval before posting, to avoid noise. Or: post directly and immediately link the issue URL in the response so the operator can close it.

Acceptance

• Tool registered in the voice/web tool catalog
• Posts to heavygee/hapi only (hardcoded -- defence against accidental upstream posts)
• Creates future-idea label if missing
• Issue body includes a footnote linking back to the originating session
• Operator setting to enable/disable

Notes

• Adjacent to existing messageCodingAgent -- same shape, different sink.
• Future: also dispatch agents to act on these issues (see Tooling: agent-driven fileFutureIdea tool that posts to fork issues #10 controlplane dispatcher).