Add binary-path GitHub Actions reference workflow

[Ayush7614]

Summary

• Add examples/github-actions/binary-path-telemetry.yml showing how to provision beacon and beacon-otelcol side by side and pass binary-path for air-gapped or self-hosted runners.
• Document the pattern in CI telemetry export docs and link it from cli/beacon/README.md.

Background

action.yml already documents binary-path for air-gapped/self-hosted runners and skips release download when it is set, but there was no copy-paste reference workflow. No open issues or PRs target this gap.

Test plan

• Verified examples/github-actions/binary-path-telemetry.yml parses as valid YAML
• Confirmed inputs match action.yml (binary-path, with beacon-otelcol adjacent)
• Ran go test ./internal/ci/... in cli/beacon
• Maintainer can copy the workflow into a test repo (or replace the provision step with an internal mirror copy) and run workflow_dispatch

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Note

Low Risk
Documentation and an example workflow only; no changes to action runtime behavior or application code.

Overview
Adds a copy-paste reference workflow for CI telemetry when runners must not download Beacon during the action step.

examples/github-actions/binary-path-telemetry.yml shows provisioning beacon and beacon-otelcol side by side (with optional checksum-verified download, or an internal mirror on air-gapped runners), then invoking the composite action with binary-path so release download is skipped.

cli/beacon/README.md and docs/log-forwarding/ci-telemetry-exports.mdx document the air-gapped/self-hosted pattern and link to the new example alongside existing GitHub Actions samples.

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