test(budgets): iron-honest wall-clock budgets — 3x the worst honest-iron measurement

Seven micro-budget tests were calibrated on one fast desktop and failed on
other honest iron with zero functional failures (bisect-proven pre-existing;
David-waived for 10.1/10.2 with this recalibration filed as the cure). Every
budget is now at least 3x the worst measurement observed across three
machines, each with a comment naming its calibration basis; the find-unified
micro-comparison of two sub-millisecond timings becomes a ratio assertion
(absolute equality of microsecond pairs can never be stable). The
inference-bound trim-history correctness test gets a timeout covering its
slowest observed run (174s) — its assertions are exact and untouched.

These remain order-of-magnitude guards; real perf enforcement lives in the
dedicated perf lanes with iron-specific budgets, per the gate-speed standard.

Known non-test artifact, documented not hidden: on slow-inference machines a
minutes-long awaited-embed loop can trip vitest's worker-RPC 60s tolerance
('Timeout calling onTaskUpdate') — all tests pass, vitest exits 1 on the
unhandled orchestration error. The CI lanes on faster iron exit clean; if a
lane ever trips it, the test moves to deterministic embeddings (its
assertions are size-bookkeeping, not embedding quality).

tests/unit/brainy/add.test.ts

@@ -452,9 +452,11 @@ describe('Brainy.add()', () => {
       })
       
       // Act & Assert
+      // order-of-magnitude guard: worst honest-iron measurement 105ms
+      // (5% over the old 100ms budget), 3x headroom on the overage class
       await assertCompletesWithin(
         () => brain.add(params),
-        100, // Should complete within 100ms
+        300,
         'Add operation'
       )
     })