fix: repair configured plugin installs (#76129)

Summary:
- The PR adds a 2026.5.2 doctor repair pass for actively used configured downloadable plugins, prefers ClawHub ... pm fallback, records installed plugin state, extends upgrade-survivor coverage, and updates docs/changelog.
- Reproducibility: yes. Static inspection of current main and the PR head gives a high-confidence reproduction ... d-plugin install pass, while the PR tests the new repair-only path, success stamping, and warning behavior.

ClawSweeper fixups:
- Included follow-up commit: test: cover configured plugin install update path
- Included follow-up commit: test: isolate channel option metadata cache
- Included follow-up commit: fix: keep configured plugin repair scoped

Validation:
- ClawSweeper review passed for head d3519ce42c.
- Required merge gates passed before the squash merge.

Prepared head SHA: d3519ce42c
Review: https://github.com/openclaw/openclaw/pull/76129#issuecomment-4364120658

Co-authored-by: Peter Steinberger <steipete@gmail.com>

scripts/lib/docker-e2e-plan.mjs

@@ -74,6 +74,7 @@ const UPGRADE_SURVIVOR_SCENARIOS = [
   "feishu-channel",
   "bootstrap-persona",
   "plugin-deps-cleanup",
+  "configured-plugin-installs",
   "tilde-log-path",
   "versioned-runtime-deps",
 ];