Add Envoy Gateway compatibility

[hunterx-code]

Summary

• Add Envoy Gateway to the compatibility matrix.
• Add a scraper for the official Envoy Gateway release compatibility matrix.
• Use GitHub release tags to select the latest stable patch release for each supported series.

Sources:

• https://gateway.envoyproxy.io/news/releases/matrix/
• https://gateway.envoyproxy.io/latest/install/install-helm/
• https://github.com/envoyproxy/gateway/releases

Note: the upstream OCI chart currently documents --version v0.0.0-latest, and the release Chart.yaml uses version: v0.0.0-latest with appVersion: latest, so this table records application compatibility without inventing per-release chart versions.

Test Plan

Test environment: not deployed; compatibility data-only change.

• Ran the scraper against the upstream compatibility matrix and release tags.
• Ran python -m py_compile utils/compatibility/scrapers/envoy-gateway.py.
• Checked manifest, per-app YAML, and aggregate YAML consistency.
• Ran git diff --check.

Checklist

• I have added a meaningful title and summary to convey the impact of this PR to a user.
• If required, I have updated the Plural documentation accordingly.
• I have added tests to cover my changes.
• I have deployed the agent to a test environment and verified that it works as expected (required only when changing agent code).

[greptile-apps]

Greptile Summary

This PR adds Envoy Gateway to the compatibility matrix by introducing a new scraper, a per-app YAML, and entries in the aggregate YAML and manifest. The scraper fetches the upstream Markdown compatibility table, dynamically locates column indices by header name, paginates the GitHub tags API to resolve the latest stable patch for each minor series, and emits warnings for any unmatched series.

• Scraper (envoy-gateway.py): Implements dynamic header detection, paginated tag resolution, and a print_warning for skipped series — all in line with patterns used by peer scrapers like external-secrets.py.
• Static data (envoy-gateway.yaml, compatibilities.yaml): 14 versions spanning 0.2.0–1.8.1 with correct kube compatibility ranges; no chart_version is intentionally omitted because the upstream OCI chart uses a fixed v0.0.0-latest tag.
• Manifest ordering: envoy-gateway is inserted between descheduler and external-dns, which is alphabetically correct.

Confidence Score: 5/5

Safe to merge — changes are limited to a new scraper and static compatibility data with no impact on application runtime.

All four changed files are additive: a new Python scraper and three YAML data files. The scraper follows established codebase patterns, previously-raised review concerns have been addressed (dynamic header detection, warning for skipped series, correct manifest ordering), and the intentional omission of chart_version is well-documented in the PR description.

No files require special attention.

Important Files Changed

Filename	Overview
utils/compatibility/scrapers/envoy-gateway.py	New scraper for Envoy Gateway compatibility matrix; dynamically detects column headers, paginates GitHub tags API, and emits warnings for unmatched series — all previously-flagged issues are resolved.
static/compatibilities/envoy-gateway.yaml	New per-app compatibility YAML; structure matches other scraped apps; no chart_version set (intentional — OCI chart pins to v0.0.0-latest per PR description).
static/compatibilities/manifest.yaml	envoy-gateway inserted between descheduler and external-dns, which is alphabetically correct ('envoy' < 'external').
static/compatibilities.yaml	Aggregate compatibility YAML updated with envoy-gateway entry; versions, kube ranges, and metadata all consistent with the per-app YAML.

_{Reviews (2): Last reviewed commit: "Tighten Envoy Gateway compatibility scra..." | Re-trigger Greptile}

[hunterx-code]

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