Add Tate Programs x402 readiness provider

[TateLyman]

Adds Tate Programs as an x402/agent-skill trust provider with three JSON POST routes:

• x402 launch-surface triage
• x402 index/discovery watch
• Agent Skill Trust Check

The upstream is https://the402.tateprograms.com and expects marketplace-managed auth via X-Tate-Provider-Token using the TATE_PROGRAMS_PROVIDER_TOKEN environment variable.

The public direct x402 versions of these endpoints are already live on Base USDC; these provider routes are the proxy-friendly upstream paths for marketplaces that collect payment before calling the provider.

Validation performed locally:

python3 - <<'PY'
import yaml
with open('providers/tateprograms.yaml') as f:
    data = yaml.safe_load(f)
assert data['id'] == 'tateprograms'
assert len(data['routes']) == 3
PY