Fix plugin catalog bridge dependent checks

[lucarlig]

Summary

• add retry_with_backoff to the expected cpex_framework_bridge dependents
• make CI Plugin Catalog run when Rust Python package Cargo.toml files change

Why

PR #91 added a cpex_framework_bridge dependency to retry_with_backoff, but CI Plugin Catalog did not run because its path filters ignored plugin Cargo.toml files. A later unrelated workflow change exposed the stale expectation.

Verification

• python3 -m unittest tests.test_plugin_catalog.PluginCatalogTests.test_framework_bridge_mutation_dependents_match_real_manifests tests.test_plugin_catalog.PluginCatalogTests.test_framework_bridge_mutation_job_uses_real_dependents
• python3 -m unittest tests/test_plugin_catalog.py

[msureshkumar88]

.github/workflows/ci-plugin-catalog.yaml L9, L17: plugin-manifest.yaml not in path triggers — adding cpex_framework_bridge to a plugin manifest without touching Cargo.toml won't fire this CI. Low risk in practice (Rust bridge deps always require both files), but the path filter should be symmetric. Add: plugins/rust/python-package/*/plugin-manifest.yaml alongside the new Cargo.toml glob on both the push and pull_request triggers.