OSOE-1284: Fix deprecations in common workflows

[Piedone]

Fixes #630 by removing the remaining Node.js 20 action runtimes from common workflows.

• Replace buildsville/add-remove-label with GitHub CLI calls, preserving single/plural labels and no-op behavior outside issue/PR events. Label removal is idempotent; API failures now fail the step rather than being swallowed.
• Replace Catchpoint telemetry with pinned dev-hato/actions-workflow-metrics v0.0.8 (Node.js 24), producing CPU/memory Mermaid charts and JSON artifacts without an external chart service. Preserve token fallback and sampling frequency. Document removed process-trace/comment/theme inputs and private-repository permissions.
• Execute the existing pinned Twitter, together! bundle under Node.js 24 for preview and posting. Add Renovate tracking for the bundle revision.
• The existing eps1lon/actions-label-merge-conflict v3.1.0 pin already uses Node.js 24; no further change is needed.
• Update affected action/workflow references to issue/OSOE-1284 for PR validation.

Validation: label regression tests passed; all changed YAML passed yamllint; changed workflows passed actionlint; git diff --check passed. Added Ubuntu and Windows CI tests for label handling and telemetry cleanup/artifact generation.

The pinned Twitter bundle passed 30 of 31 upstream scenarios under Node.js 24 using nock 14 for native-fetch mocking and Linux line-ending behavior on the Windows test host. The remaining scenario exposes an existing bundled-code mismatch: a preview of a tweet without a trailing newline includes the diff's "No newline at end of file" marker. The bundle is unchanged by this PR. No real X posts were made. The bundle also emits its existing dependency's punycode deprecation notice under Node.js 24; the deprecated action-runtime declaration is no longer used.

The pnpm/action-setup update is in the companion NodeJs-Extensions PR; the superproject PR updates the submodule pointer and consumes these branches. Telemetry no longer supports process traces or PR comments; see Docs/Workflows.md for migration details.

Companion PRs: Lombiq/NodeJs-Extensions#175 and Lombiq/Open-Source-Orchard-Core-Extensions#1334.

CI verification: Ubuntu and Windows label/telemetry smoke jobs passed and produced metrics artifacts; YAML, spelling, branch-reference, and PR validation checks passed. New PowerShell scripts also pass the repository's custom analyzer rules locally. The superproject allowlist permits the telemetry action, and its root-solution and NuGetTest build-and-test jobs passed with metrics artifacts uploaded. See https://github.com/Lombiq/Open-Source-Orchard-Core-Extensions/actions/runs/33988394245.
Nested-call regression: JSON secrets must be constructed as a single line in the caller. GitHub masks individual lines of multiline secrets before actions start; standalone braces otherwise corrupt Mermaid charts and their legends. Updated all ENVIRONMENT_VARIABLES_JSON examples to folded blocks with equally indented lines, documented the cause, and added a two-level reusable-workflow regression. Ubuntu and Windows jobs both passed, preserving chart braces while masking synthetic credentials and uploading metrics artifacts: https://github.com/Lombiq/GitHub-Actions/actions/runs/34058180250.
Cross-repository telemetry authentication: the three build-and-test workflows now pass github.token to telemetry instead of CHECKOUT_TOKEN. Telemetry lists jobs in the original caller repository; a PAT that can check out another private repository may not be able to read the caller's Actions run, resulting in a post-job 404. The checkout token remains unchanged. The caller's GITHUB_TOKEN needs actions:read, as documented. Verified token selection and checkout-token preservation in all three parsed workflows; yamllint, actionlint, and git diff --check pass.