Miner dashboard chat: discover/attempt action-dispatch

[JSONbored]

Context

Part of epic #6504's chat track, blocked on the action-dispatch scaffolding child issue of this same epic. discover/attempt are CLI-only today (packages/loopover-miner/discover-cli.js, attempt-cli.js) with no HTTP route, unlike portfolio release/requeue and governor pause/resume which already have API routes the existing dashboard buttons call.

Requirements

• Add new API routes for discover/attempt mirroring the existing action-button pattern used by /api/portfolio-queue/{release,requeue} and /api/governor/{pause,resume}.
• Wire chat's action-dispatch layer (from the scaffolding child issue) to call these new routes — never the underlying CLI/store directly.
• These new routes must themselves route through the same Governor chokepoint / PreToolUse deny-hook path every other local write already goes through.

Deliverables

• New discover/attempt API routes
• Chat wiring through the action-dispatch layer
• Test coverage including a regression test confirming the chokepoint/deny-hook path is exercised

Test Coverage Requirements

99%+ Codecov patch coverage on every changed line and branch, plus a regression test for the new/changed behavior (note: apps/** UI code may fall outside the strict Codecov patch gate — check coverage.include — but a before/after screenshot table per this repo's UI-PR convention is still required for any visual change).

Expected Outcome

Chat can trigger discover/attempt runs through a properly-governed API route, matching the safety discipline of every other chat action.

Links & Resources

Epic: #6504. Blocked by the "action-dispatch scaffolding" issue in this same epic. packages/loopover-miner/discover-cli.js, attempt-cli.js.

[linear-code]

JSO-4720