Use timeout_seconds for web fetch and search tools - #41

Summary

• Rename web_fetch timeout to timeout_seconds and explicitly document seconds, retaining the 30-second default and 120-second cap.
• Add web_search timeout_seconds as a per-call override, preserving the internal timeoutMs option and 25-second fallback.
• Use an Effect-clock search timer and injectable fetch for deterministic regression tests.

Verification

• fold-agent and fold-core suites: 554 tests passed
• Repository typecheck and format check passed
• Lint: 0 errors (27 warnings)
• Independent review and focused rerun: 23 tests passed

Rollout

The agent-facing web_fetch field is intentionally renamed without retaining the ambiguous timeout alias. After merge, publish a new Fold release, then update the pinned Fold dependencies in SyncLayer’s Riptide daemon (currently 0.1.24). No release tag or SyncLayer dependency changes are included here.