fix: move sink-visibility to env var to prevent zizmor template-injection (#48589)

* Initial plan

* fix: move sink-visibility to env var to prevent zizmor template-injection

- Change sinkVisibilityRuntimeExpr from a raw ${{ }} expression in the
  run: heredoc to ${GH_AW_SINK_VISIBILITY} shell variable reference
- Add GH_AW_SINK_VISIBILITY env var to Start MCP Gateway step's env:
  block, set from ${{ toJSON(steps.determine-automatic-lockdown.outputs.visibility) }}
- Add -e GH_AW_SINK_VISIBILITY to MCP gateway Docker container flags
- Add GH_AW_SINK_VISIBILITY to buildAddedGatewayEnvVarSet to prevent
  duplicate emission
- Add --persona auditor to internal zizmor invocation
- Update test to check for GH_AW_SINK_VISIBILITY instead of old expression
- Regenerate 263 lock files via make recompile

Fixes #48565

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* fix: set GH_AW_SINK_VISIBILITY for gh-proxy mode workflows

The initial fix only added GH_AW_SINK_VISIBILITY to the env block when
'github' was present in mcpTools. For gh-proxy mode workflows, GitHub is
excluded from mcpTools (because it's handled via CLI proxy instead of MCP
server), but determine-automatic-lockdown still runs and sink-visibility
is still emitted in the MCP gateway config JSON.

Move the GH_AW_SINK_VISIBILITY env var assignment to check tools["github"]
directly (same condition as generateGitHubMCPLockdownDetectionStep), so
all workflows with the GitHub tool get the env var regardless of mode.

Also update golden test files to reflect the new env var and docker flag.

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* fix: remove toJSON() from GH_AW_SINK_VISIBILITY to fix double-encoding

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* Add changeset for sink visibility fix

* fix: rebase PR 48632 fixes - add sinkVisibilityEnvVar constant, sorted policy iteration, and case string handler

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Peli de Halleux <pelikhan@users.noreply.github.com>

Author: 3 people