[TheGreatAxios]

Summary

@corbits/catalog-tools (list_model_concepts, pick_models,
estimate_run_cost) no longer talks to a Workbench-only hub route. It now
reads two stock Interchange tenant routes with the run's own bearer, and
resolves the model chain itself:

• GET /api/tenants/:tenantId/models — the bench's resolved model catalog
  (offerings + active price per currency), flattened by the new
  @corbits/inference-catalog catalog.ts into the plain rows
  resolveModelChain ranks.
• GET /api/tenants/:tenantId — the bench itself, for its model policy at
  config.corbits.modelPolicy (schema and reader in
  @corbits/inference-catalog/policy.ts).

Deleted: packages/inference-catalog/src/workflow-catalog-routes.ts, its
pg-store/migrations/schema (bench_model_policy table), and the hub's
/api/workflow-inference-catalog mount. There is no hub-side chain
resolution left for this bundle — it all runs in the workflow child
(packages/catalog-tools/src/chain.ts).

corbits.modelPolicy config shape

{
  "corbits": {
    "modelPolicy": {
      "allow": ["string selectors"],       // canonical name | "provider:<name>" | "<provider>/<name>"
      "deny": ["string selectors"],
      "maxInputUsdPerMTok": 3.0,           // or null
      "maxOutputUsdPerMTok": 15.0,         // or null
      "ceilingIsHard": false,              // soft (demote) vs hard (exclude)
      "conceptCeilings": {
        "<conceptId>": { "maxInputUsdPerMTok": 50, "maxOutputUsdPerMTok": 100 }
      },
      "providerPreference": { "mode": "pin" | "prefer", "order": ["providerName"] } // or null
    }
  }
}

Every key is optional; a missing or malformed blob reads as
EMPTY_POLICY (unconstrained), never an error.

Notes for reviewers

• This finishes CL-8170, picking up a branch a prior agent left mid-fix.
  My work here was: rewriting the stale resolve-chain.test.ts,
  price.test.ts, client.test.ts, tool.test.ts and
  test/fixtures.ts against the new pure CatalogOffering/
  CatalogPricingRow shapes (no more asOf/connectivity/provenance
  concerns, since those are the platform's own job now); bumping
  @corbits/catalog-tools to 0.1.0 and its pin in
  workflows/assistant/src/prompt.ts; regenerating tsconfig references
  and the changeset ignore list; and rebasing onto origin/main (which
  had, unrelated to this PR, deleted @corbits/bench and its
  bench-settings mount — cleaned up a stray reintroduction of that dead
  code from the rebase's own conflict resolution).
• bun run typecheck, bun test (workspace-wide check:structural
  suite included), and bun run lint are all green locally.

Test plan

• bun run typecheck
• bun test packages/catalog-tools packages/inference-catalog
• bun run lint
• bun run check:structural
• CI

[linear-code]

CL-8170