Task: Install the server child-friendly replies plugin by default

Identity

Task ID: 20260928-default-child-replies-0108dd01
Mode: Feature
Branch: codex/20260928-default-child-replies-0108dd01-default-child-replies
Worktree: D:\Datas\OthersProjects.codex-worktrees\makelore\20260928-default-child-replies-0108dd01
Base commit: efff238a75
Owner: codex
Status: Ready for Integration

Automatically acquire and install the signed server plugin makelore.child-friendly-replies on session activation and Library refresh. Update the Main facade/composition, focused tests, Electron projection acceptance and README.

User requests default installation. Preserve account isolation, server-signed immutable artifacts, existing client trusted-key verification and device package lifecycle. Do not turn install into project enablement or Agent assignment. Account removal and default-plugin uninstall are explicit opt-outs.
Official check/start/status passed for the isolated feature Identity. Planning Gate passed after own task, entry/memory, positioning/current-state/decisions/architecture/domain/success/evidence and 135 peer coordination records. Positioning still includes template text; AGENTS/README and current source establish product meaning. Old Marketplace tasks overlap paths but preserve the same contracts; no semantic conflict found. Primary main remains owned by integration task 20260928-merge-teacher-cards-a09c07f3 and is untouched.
User-provided no-subagent constraint honored. Feature code and mandatory task record only; canonical docs remain unchanged. WS companion task 20260928-default-child-replies-06693309 owns readiness repair.

Main acquires/downloads only this default plugin through existing Marketplace and Package Store APIs, after confirming a fresh signed compatible Artifact release. Existing installed packages are reused; removed/suspended/stale entries remain unchanged, and failed downloads retry on a later session/list refresh.
Facade serializes account operations so an explicit removal during default installation wins, and verifies account binding around queued work. Default-plugin uninstall writes the existing account removal receipt, preventing reinstallation on restart; other plugin/device semantics remain unchanged.
Composition starts the normal Library flow when initialized and on session changes. Successful package installation invalidates managed resources through the existing callback. Renderer still receives only safe installation projections; original Skill bytes remain server-delivered.
Updated Electron fixture verifies the default plugin appears in the Installed tab without an install click, alongside the existing optional acquisition flow. Updated a stale header-copy assertion to the actual tab landmark for the current embedded drawer.

Red: five default-install facade tests failed before implementation (no install, no opt-out, no retry, no account-switch rejection). Final focused run: 70 unit tests passed across default installation, facade, Marketplace client, routes and plugin composition; separate composition image/background-sleep run: 9 passed (overlap in plugin composition).
Six default-install scenarios cover first install, reuse, explicit uninstall/removal, unsigned package deferral, download retry, account change and removal while installation is pending.
Pinned pnpm 10.33.4 frozen offline install, standard typecheck, changed-file ESLint and production build:vite passed. Electron default Installed-tab/optional acquisition scenario: 1 passed. E2E uses a Main API fixture for display; signed network/package validation remains covered by the existing client tests and companion server acceptance, not a real production install.
git diff --check passed; final task-aware drift check required before completion. No packaging, installed-app update, push, production mutation or paid call occurred.

Merge verified source after the primary main ownership handoff is authorized. Ship updated client and companion WS startup-signing repair; deploying only the server cannot make an old client automatically install packages.

Target current-state and product README: the specific server Skill is installed by default through the signed Marketplace path on session/list refresh, with removal retained and project/Agent controls unchanged. Evidence: focused red/green tests, production build and Electron Installed-tab projection. User requested behavior; no architecture reversal or additional product decision needed.