Skip heavy CI jobs (Go test/lint/build, web, integration) for docs-only changes

What would you like to be added:

Skip the heavy CI jobs (Go test/lint/build, web, integration, CodeQL) for PRs that only change documentation files (docs/**, **.md).

Currently test.yaml, build.yaml, lint.yaml, gen.yaml, and codeql-analysis.yaml run on every PR with no path filters, so even a docs typo fix runs the full Go test/lint matrix (one job per module), govulncheck, web tests, and integration tests.

Note: go-test-completed and go-lint-completed are required checks, so a plain paths-ignore on the triggers would leave them stuck at "Expected" and block merging. Instead, a first job can detect changed paths (e.g. dorny/paths-filter) and the heavy jobs skip conditionally the existing *-completed gate jobs still report success, so required checks keep working.

Why is this needed:

Docs-only changes cannot affect test/lint/build results, so running these jobs wastes CI compute and runner queue slots, and slows down feedback for docs contributors.