ci: add shared security scanning workflow

[opentelemetrybot]

Tracked in open-telemetry/sig-security#293.

Adds zizmor scanning through the OpenTelemetry shared workflow.

The workflow:

• runs the regular persona on pull requests, pushes to main, and a randomized weekly schedule;
• uploads results to GitHub code scanning;
• uses the shared workflow pinned to an immutable commit.

After merge

1. Confirm the Zizmor workflow succeeds on the merged default-branch commit and its code-scanning analysis has no findings.
2. Mark the corresponding admin PR ready for review and merge it to require zizmor code scanning.
3. On the next repository pull request, confirm GitHub reports a required zizmor code-scanning result.

If enforcement unexpectedly blocks a valid change, restore require_zizmor = false in open-telemetry/admin while leaving scanning enabled.

[github-advanced-security]

You are seeing this message because GitHub Code Scanning has recently been set up for this repository, or this pull request contains the workflow file for the Code Scanning tool.

What Enabling Code Scanning Means:

• The 'Security' tab will display more code scanning analysis results (e.g., for the default branch).
• Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results.
• You will be able to see the analysis results for the pull request's branch on this overview once the scans have completed and the checks have passed.

For more information about GitHub Code Scanning, check out the documentation.

[Copilot]

Pull request overview

Adds Zizmor GitHub Actions workflow scanning via the OpenTelemetry shared reusable workflow, and hardens existing GitHub Actions workflows by pinning actions to immutable SHAs and reducing token persistence.

Changes:

• Add .github/workflows/zizmor.yml to run Zizmor (regular persona by default) and upload SARIF results to GitHub code scanning.
• Pin multiple GitHub Actions dependencies to commit SHAs and set persist-credentials: false for checkouts across workflows.
• Add a Dependabot GitHub Actions update cooldown to reduce churn from newly released versions.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
.github/workflows/zizmor.yml	New reusable-workflow caller to run Zizmor and upload SARIF to code scanning.
.github/workflows/webserver.yml	Pin actions to SHAs, add persist-credentials: false.
.github/workflows/user_events.yml	Pin checkout to SHA and disable credential persistence for both checkouts.
.github/workflows/spdlog.yml	Pin checkout to SHA and disable credential persistence for both checkouts.
.github/workflows/prometheus.yml	Pin checkout/cache actions to SHAs and disable credential persistence.
.github/workflows/ossf-scorecard.yml	Align pinned action version comments and keep checkout non-persistent.
.github/workflows/nginx.yml	Pin actions to SHAs, add Zizmor ignore annotations, disable credential persistence.
.github/workflows/log4cxx.yml	Pin checkout to SHA and disable credential persistence for all checkouts.
.github/workflows/httpd.yml	Pin checkout/upload-artifact to SHAs and disable credential persistence.
.github/workflows/glog.yml	Pin checkout to SHA and disable credential persistence for all checkouts.
.github/workflows/geneva_trace.yml	Pin checkout to SHA and disable credential persistence.
.github/workflows/geneva_metrics.yml	Pin checkout to SHA and disable credential persistence for both checkouts.
.github/workflows/fossa.yml	Align pinned checkout version comment and disable credential persistence.
.github/workflows/fluentd.yml	Pin checkout to SHA and disable credential persistence for both checkouts.
.github/workflows/boost_log.yml	Pin checkout to SHA and disable credential persistence for both checkouts.
.github/dependabot.yml	Add Dependabot cooldown to delay version-update PR creation.

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[thompson-tomo]

Let's get #641 & #654 merged as well as the renovate ci pr's which will be raised, so that we have confirmation that the dependencies will be managed.

In relation to CI failures #633 will enable some of the checks to now pass.

[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated no new comments.

Suppressed comments (1)

.github/workflows/zizmor.yml:7

• pull_request trigger is missing a branches filter. In this repo, other workflows consistently scope PR triggers to the main base branch (e.g., .github/workflows/nginx.yml:12-16, .github/workflows/prometheus.yml:9-13). Without the filter, this will run on PRs targeting any branch, which may be unintended and increases CI/code-scanning noise.

on:
  push:
    branches: [main]
  pull_request:
  schedule:

[dbarker]

I've disabled all the broken workflow jobs to unblock this PR. Follow up investigations needed to enable the broken workflows.