chore: update repo-assist MCPG container image to v0.1.26

[lpcox]

Summary

Switch repo-assist from local container build to published image v0.1.26, which includes all DIFC integrity filtering fixes:

• Backend enrichment tool name fix (PR fix(guard): correct backend enrichment tool names and args #2340): corrected get_pull_request → pull_request_read and added missing method: "get" parameters
• Sub-method response labeling skip (PR guard: GraphQL response labeling, backend enrichment, and sub-method skip #2335): prevents mislabeling get_check_runs/get_comments sub-method responses
• isError response skip (PR guard: GraphQL response labeling, backend enrichment, and sub-method skip #2335): avoids labeling 404/error responses as domain objects
• Search scope extraction (PR guard: GraphQL response labeling, backend enrichment, and sub-method skip #2335): enables filtering for search_issues/search_pull_requests

Changes

• Comment out local container build step (kept as comment for future debugging)
• Update proxy image tag: :local → :v0.1.26
• Update MCP gateway image tag: :local → :v0.1.26

Validation

v0.1.26 was validated with 0 DIFC-FILTERED events in run 23412918230.

[Copilot]

Pull request overview

Updates the repo-assist locked workflow to use the published ghcr.io/github/gh-aw-mcpg:v0.1.26 image instead of building/running a local :local tag, aligning repo-assist with the validated MCPG release that contains DIFC integrity filtering fixes.

Changes:

• Commented out the local MCPG container build step (kept for debugging).
• Updated the DIFC proxy container invocation to ghcr.io/github/gh-aw-mcpg:v0.1.26.
• Updated the MCP gateway container command to run ghcr.io/github/gh-aw-mcpg:v0.1.26.

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[Copilot]

This change switches the proxy container to ghcr.io/github/gh-aw-mcpg:v0.1.26, but the workflow’s earlier "Download container images" step doesn’t pre-pull this image (unlike other *.lock.yml workflows that include gh-aw-mcpg in download_docker_images.sh). That means this step will do an on-demand pull at runtime, which can add latency and can fail in restricted network environments. Consider adding ghcr.io/github/gh-aw-mcpg:v0.1.26 to the image pre-pull list (or doing an explicit docker pull) to keep startup deterministic.

[Copilot]

The note suggests uncommenting this step is sufficient to test unpublished MCPG changes, but the rest of the workflow now runs ghcr.io/github/gh-aw-mcpg:v0.1.26 (not :local). If someone uncommented just this step, it would build :local and then never use it. Consider updating the comment to mention the other image references that must be switched, or parameterize the image tag so the debug flow is a simple toggle.