[Creator] Add gcp-apigee-traffic-health CodeBundle (#158)

[rw-codebundle-agent]

Closes #158

Summary

Implements the gcp-apigee-traffic-health CodeBundle per the attached design spec. This bundle monitors the runtime traffic, performance, and reliability of Apigee API proxying via Cloud Monitoring.

What it monitors

• Discovery: Enumerates Apigee proxies, environments, and target servers at org scope (discover_metrics_scope.sh)
• Error/fault rates: Flags proxies whose 4xx/5xx or fault rate exceeds ERROR_RATE_THRESHOLD (check_error_rates.sh)
• Latency performance: Flags proxies whose p95/p99 latency exceeds LATENCY_MS_THRESHOLD (check_latency.sh)
• Throughput/anomalies: Flags anomalous traffic and Apigee-detected anomalies (check_throughput.sh)
• Target/backend performance: Flags degraded target servers (check_target_performance.sh)
• Traffic summary: Aggregates findings into a consolidated health summary (generate_traffic_summary.sh)

Includes an in-repo sli.robot producing a 0-1 health score across four dimensions (error rate, latency, throughput, target), plus sli in the generation rules outputItems and a *-sli.yaml template.

Test strategy

Deterministic mock-based tests under .test/ covering the design-spec scenarios (healthy_traffic, high_error_rate, high_latency_and_slow_target), run via validate-all-tests.sh / task run-mock-tests. A lightweight Terraform scaffold is included for optional future integration testing.

Validation

• Scorer: 104/104 (PASS, threshold 70)
• All 18 mock test assertions pass

Deviations from spec

• Used qualifiers: ["project", "resource"] (GCP platform supports only project and resource qualifiers) instead of an "organization" qualifier.
• Metric names validated against Cloud Monitoring docs (apigee.googleapis.com/proxyv2/request_count confirmed real).

[Rohit-Ekbote]

Closing as a duplicate of #731.

The creator bot opened this spec twice — once on codebundle/gcp-apigee-traffic-health, once on creator/issue-158. Both PRs point at the same single commit efcf6e47, so the diffs are byte-identical (+2277/-0 across 40 files).

Keeping #731, since creator/issue-N is the branch every merged Apigee bundle came from (#744, #745, #746, #748). The gcp-apigee-traffic-health work itself is still wanted — throughput/anomaly detection and target-server performance are not covered by anything on main. Review continues on #731.

No content is lost by this close.