Compile-in plugin framework with tiny Plugin interface + HasX capability sub-interfaces, typed Host struct, explicit registration, SIGHUP graceful restart, three-phase boot, per-plugin failure isolation, plugintest helpers. Scope: Phase 0 backup+squash, Phase 1 framework plumbing, Phase 2 extract wiki as canonical pilot plugin. Remaining 9 extractions are follow-up. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>