chore: apply plugin version discipline

[intel352]

Part of GoCodeAlone/workflow#760.

Changes:

• keep committed plugin.json.version at the 0.0.0 development sentinel
• remove the obsolete sync-plugin-version workflow when present
• add post-build release validation so the shipped manifest is checked against the tag
• preserve/strengthen runtime capability checks where needed

Verification:

• wfctl plugin validate-contract .
• wfctl plugin validate-contract --for-publish --tag v9.9.9 .
• GOWORK=off go test ./...

[Copilot]

Pull request overview

Applies “version discipline” for plugin manifests by keeping the committed plugin.json at a development sentinel version while tightening CI/release validation to ensure the published artifacts are still correctly rewritten and verified.

Changes:

• Set committed plugin.json.version to 0.0.0 (development sentinel) while relying on GoReleaser rewrite hooks for real releases.
• Update tests to validate download URL shape independent of the release tag, and to run all matching GoReleaser rewrite hooks.
• Extend the release workflow with runtime verify-capabilities and a post-build publish validation step.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
plugin.json	Set committed manifest version to 0.0.0 sentinel.
internal/plugin_test.go	Normalize release tag in download URL assertions; execute all matching GoReleaser rewrite hooks.
.github/workflows/release.yml	Add runtime capability verification and post-build contract validation in the release job.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.