test(runtime-host): wait helpers poll on fixed tick budgets and can flake under load

## Problem

Following the same failure class as #4383 (fixed for `packages/runtime` in #4387): several `packages/runtime-host` test helpers poll for an asynchronous condition with a fixed count of macrotask ticks instead of a wall-clock deadline. The tick count is not a time budget — under a loaded CI runner the underlying work (turn settlement over UDS connections, agent-graph wake-run persistence, peer mesh roster propagation, provider request capture persistence) can span more ticks than the loop allows, so the helper gives up before the condition is genuinely false and the test reports a failure that cannot be distinguished from a real regression.

## Inventory

Fixed-tick polling loops in `packages/runtime-host/src/__tests__`:

- `execution-model-composition.test.ts` — the graph-wake loop (400 ticks), `startTurn` (200), `waitForTerminal` (200), `waitForUsage` (100), `waitForCanonicalAttempts` (100), `waitForCaptureArtifacts` (100), `waitForAutomaticMemoryRequestsToSettle` (100)
- `plan-two-client-uds.test.ts` — `waitForTerminal` (100), polling `turn.query` over a real UDS connection
- `runtime-policy-coordinator.test.ts` — inline turn-settlement loop (100 × 20ms)
- `peer-mesh.test.ts` — roster propagation loop (20 × 10ms; a 200ms budget over real serve/join networking)
- `peer-native.test.ts` — `waitForRequestCount` (10 immediates)

The in-memory `setImmediate` helpers (`waitForPending` in `client-capability-admission-integration.test.ts`, `waitForGoalRun` in `goal-root-authority.test.ts`) are intentionally out of scope: they poll in-memory facades where a tick budget is effectively unbounded.

## Desired outcome

Convert the listed loops to the shared `waitFor` primitive from `@maka/core/test-only/async-primitives` with an explicit wall-clock deadline (5s) and a small poll interval, keeping each helper's failure message. Production behavior is unchanged; this is test-infrastructure only.

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Automated disclosure: this issue was drafted by Claude at @qianzhu18's direction. @qianzhu18 remains the human contributor of record.