Salvaged from PR #64188 (@Bartok9), re-reviewed against the #64229
ownership ledger (landed in #84923).
Delivery parity (survived):
- Module-level invoke_hook/invoke_middleware/has_hook/has_middleware
lazily run plugin discovery via _delivery_manager(), so surfaces that
never import model_tools (dashboards, TUI slash workers, query mode,
cron, gateway platform events) deliver plugin callbacks instead of
silently dropping them (#50776, #67597, #67890, #50937).
- _delivery_manager() joins any in-flight background discovery first and
tolerates test doubles that monkeypatch get_plugin_manager().
Symmetric force-reload (survived):
- agent/shell_hooks.py gains re_register_config_hooks(); the force branch
of discover_and_load() calls it after a successful sweep, restoring
config.yaml shell hooks that the ledger-driven unload wiped but cannot
restore (they are config-owned, not plugin-owned) (#60036).
- unload(plugin=None) now sweeps pre-ledger _plugin_tool_names entries
out of the process-global tools.registry, mirroring the platform-name
sweep that already existed, so zombie tools cannot survive a force
reload in long-lived pre-ledger processes (#60050).
Superseded by the ownership ledger (dropped from #64188):
- _unload_global_plugin_registrations() bulk tool/platform teardown —
the ledger's reverse-order handle disposal with previous-entry
restoration covers it more precisely.
- tools.registry/platform_registry displaced-entry LIFO restore stacks —
the ledger's restore_registration() identity-checked previous-entry
restoration made them redundant.
- Discovery serialization lock + double-checked singleton — main already
has _discovery_lock on every discover/unload path and a keyed,
lock-guarded per-home manager cache (#24714 concern is covered).
Fixes tracked under #64178 (#50776, #60036, #60050, #24714, #67798,
#50937, #67597, #67890, #31480 — #31480 already handled on main by
_parse_hooks_block warn+suggest).
Bartok9
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