chore: add daily Drain3 weight training workflow; delete agentdrain demo binary

[Copilot]

Addresses review feedback on #24328: remove the throwaway demo program and automate refreshing the embedded Drain3 log-pattern weights.

Changes

• Deleted cmd/agentdrain-demo/main.go — one-off exploration code, not needed in tree
• Added .github/workflows/train-drain3-weights.yml — non-agentic daily workflow that:
  • Builds gh-aw from source
  • Runs gh aw logs --train --count 50 to download recent run logs and produce drain3_weights.json
  • Copies the file to pkg/agentdrain/data/default_weights.json (the embedded defaults path)
  • Opens a PR against main when the weights change; skips PR creation if output is identical
  • Also triggerable via workflow_dispatch

[Copilot]

Pull request overview

Removes a throwaway Drain3 demo binary and adds a scheduled GitHub Actions workflow to retrain and propose updates to the embedded Drain3 default weights.

Changes:

• Deleted cmd/agentdrain-demo/main.go demo program.
• Added a daily (cron) + manual (workflow_dispatch) workflow to run ./gh-aw logs --train, update pkg/agentdrain/data/default_weights.json, and open a PR when it changes.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
cmd/agentdrain-demo/main.go	Removes non-production demo code from the repo.
.github/workflows/train-drain3-weights.yml	Automates periodic Drain3 weights training and proposes updates via PR.

Comments suppressed due to low confidence (1)

.github/workflows/train-drain3-weights.yml:73

• The branch name is only date-based (ci/train-drain3-weights-YYYYMMDD). Re-runs on the same day (manual dispatch, retries, or overlapping runs) will fail to git push due to the branch already existing.

Include a uniqueness suffix such as time (%H%M%S) or ${{ github.run_id }}. For reference, .github/workflows/format-and-commit.yml:70 uses a timestamped branch name for this reason.

          BRANCH_NAME="ci/train-drain3-weights-$(date +%Y%m%d)"

          git checkout -b "$BRANCH_NAME"
          git add pkg/agentdrain/data/default_weights.json

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[Copilot]

The job token permissions are missing actions: read, which ./gh-aw logs --train needs to list/download workflow run data. With permissions: {} at the workflow level, unspecified scopes default to none, so the logs step is likely to fail with 403.

Add actions: read to jobs.train.permissions (keep contents: write / pull-requests: write as-is). See .github/aw/debug-agentic-workflow.md:68-71 for the documented requirement.

Suggested change

	permissions:
	permissions:
	actions: read

[Copilot]

Consider adding a concurrency group for this scheduled workflow to prevent overlapping runs (e.g., if a run is slow or a manual dispatch happens near the cron time). Overlaps can lead to duplicate branches/PRs and wasted runner time.

This repo commonly uses concurrency: { group: "gh-aw-${{ github.workflow }}" } for scheduled workflows (e.g., .github/workflows/daily-integrity-analysis.lock.yml:48-50).

This issue also appears on line 70 of the same file.

[Copilot]

make build runs sync-action-pins/sync-action-scripts as prerequisites (Makefile:22,669-685), which can modify tracked files unrelated to Drain3 weights during this automation run. To avoid incidental working-tree changes and keep the workflow focused, consider building only the CLI binary via go build ... ./cmd/gh-aw (or a dedicated make build-cli target without sync steps).