Switch CLI + MCP tool from POST /api/agent/lookup to POST /api/agent/search

[A1igator]

Tenjin collapsed its agent discovery surface to ONE endpoint: POST /api/agent/lookup was deleted outright and replaced by POST /api/agent/search (no shim, no alias — there is no installed agent base, so back-compat is moot).

What changed upstream

• Endpoint: POST /api/agent/lookup → POST /api/agent/search. Same request body ({ schemaVersion, question, freshWithin?, maxPrice?, appliesTo?, limit? }) and same response contract ({ lookupId, decision: "CANDIDATES" | "MISS", calibration, candidates? }).
• The MISS browse tier renamed from related → browse (same semantics: ≤3 broad-corpus pointers, no match/confidence claims, never candidates, MISS-only).
• The outcome-reporting flow is UNCHANGED: still POST /api/agent/lookups/<lookupId>/outcomes, still keyed by the lookupId the search returns. X-Tenjin-Lookup-Id on the paid read is unchanged too.

Asks

1. Point the CLI's discovery call and the MCP lookup tool (rename it to search) at POST /api/agent/search.
2. Render the MISS browse tail as a one-line hint under a MISS (e.g. "no match — N pieces you could browse", pointers, not scored candidates).
3. No shim / no fallback to the old path needed (no install base).

Refs BackTrackCo/tenjin#463 and BackTrackCo/tenjin#460.