Changes

feat(tekton/v0): add Tekton triggers and templates for CI/CD workflows (#3768)

This pull request introduces Tekton CI/CD resource definitions to the
repository, expanding the documentation and adding several reusable
Tekton TriggerTemplates for building components across multiple
platforms. The changes improve support for modern CI/CD workflows and
clarify the organization of pipeline resources.

**Tekton CI/CD Integration:**

* Added `/tekton` as a top-level directory for Tekton static resource
definitions in the documentation, and documented naming conventions and
resource organization for pipelines, tasks, and triggers.
[[1]](diffhunk://#diff-322a2f3bc03329a02dadac1553ae905c9e2fecda474c8dce01701d2d9ccaf1a2R9)
[[2]](diffhunk://#diff-322a2f3bc03329a02dadac1553ae905c9e2fecda474c8dce01701d2d9ccaf1a2R65-R74)

**New TriggerTemplates for Component Builds:**

* Added `build-component-all-platforms.yaml`, a TriggerTemplate to
launch builds for a component across Linux (amd64/arm64) and Darwin
(amd64/arm64) platforms, with parameterization for git source, build
profile, registry, resources, and credentials.
* Added `build-component-single-platform.yaml`, a TriggerTemplate to
launch a build for a single specified platform, supporting Linux and
Darwin, with flexible parameters and workspace configuration.
* Added `build-component.yaml`, a TriggerTemplate for building a
component on Linux (amd64/arm64), parameterized for git source, profile,
registry, and resource requirements.

**CI Helper Task Integration:**

* Added `ci-helper-for-pr.yaml`, a TriggerTemplate for running a helper
CI task on pull requests, passing PR metadata and GitHub credentials.

**Documentation Updates:**

* Added a README to clarify the purpose of the new public trigger
template folder in Tekton resources.

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Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
 (commit: 8c85514)