ci: trigger eval-skills on every PR so required checks always report

[tiffanylphan]

Summary

The required checks come from a path-filtered workflow, so PRs that don't touch skills/** or evals/** never trigger it and get stuck "waiting for status to report." This PR removes the path filter so the workflow fires on every PR. Nothing is weakened: the diff job inside the workflow already gates the actual eval work on whether skills changed, and skipped required checks count as passing in branch protection. Net cost: ~40s of cheap CI per PR; no extra API tokens.

---

Branch protection on main requires three status checks — Unit tests, Aggregate scores, and Evaluate gate — all of which are produced by .github/workflows/eval-skills.yml. The workflow is currently path-filtered:

on:
  pull_request:
    paths:
      - "skills/**"
      - "evals/**"
      - ".github/workflows/eval-skills.yml"

For any PR that doesn't touch one of those paths, the workflow never triggers, so the three required checks stay forever in Expected — Waiting for status to be reported and the PR is BLOCKED from merging even with every other check green and reviews approved.

#74 hit this — it only changed .claude-plugin/marketplace.json and README.md, so the workflow never fired and the merge button has been stuck for days.

Fix

Remove the trigger-level paths: filter so the workflow runs on every PR. The cost is small:

• The diff job is preserved — it still computes whether any skills actually changed.
• evaluate and aggregate already have job-level if: needs.diff.outputs.has_changes == 'true' guards, so they skip cleanly on PRs that don't touch skills.
• GitHub treats skipped required checks as passing, so non-skill PRs still satisfy branch protection without running any actual evals.
• The only always-on cost added per PR is the unit-test job (~30s) and the diff job (~10s).

The cron-schedule and workflow_dispatch triggers are unchanged.

Test plan

• Merge this PR (it touches .github/workflows/eval-skills.yml, so the workflow self-triggers under the old paths filter — required checks will report on this PR via the existing rule).
• Confirm #74 unblocks once this lands — push an empty/no-op commit there so the new trigger fires, and verify all three required checks report SUCCESS or SKIPPED.
• Open a follow-up PR touching only a non-skills file (e.g. README.md) and confirm the three required checks report there too.

🤖 Generated with Claude Code

[github-actions]

Skill eval results

Skill	Before	After	Δ
agentcontrol/configs-create	100/100 (4/4)	75/100 (3/4)	-25
agentcontrol/configs-update	80/100 (4/5)	80/100 (4/5)	no change
agentcontrol/configs-variations	80/100 (4/5)	80/100 (4/5)	no change
agentcontrol/tools	75/100 (3/4)	75/100 (3/4)	no change
feature-flags/launchdarkly-flag-command	-	100/100 (3/3)	new
feature-flags/launchdarkly-flag-create	100/100 (3/3)	100/100 (3/3)	no change

Only suites whose source actually changed since their last recorded score were re-run. Soft-failing while we stabilise the baseline.