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>

docs/help/testing-updates-plugins.md

@@ -118,9 +118,10 @@ pnpm test:docker:published-upgrade-survivor
 ```
 
 Available scenarios are `base`, `feishu-channel`, `bootstrap-persona`,
-`plugin-deps-cleanup`, `tilde-log-path`, and `versioned-runtime-deps`. In aggregate runs,
+`plugin-deps-cleanup`, `configured-plugin-installs`, `tilde-log-path`, and
+`versioned-runtime-deps`. In aggregate runs,
 `OPENCLAW_UPGRADE_SURVIVOR_SCENARIOS=reported-issues` expands to all reported
-issue-shaped scenarios.
+issue-shaped scenarios, including the configured-plugin install migration.
 
 Full update migration is intentionally separate from Full Release CI. Use the
 manual `Update Migration` workflow when the release question is "can every