feat: move plugin workspace into project settings

.project-docs/10-decisions/proposals/20260906-move-plugins-project-settings-7c91a4e2__project-settings-plugin-navigation.md

@@ -0,0 +1,86 @@
+# Project Configuration owns Plugin navigation
+
+## Status
+
+Proposed for integration; implemented and verified in task
+`20260906-move-plugins-project-settings-7c91a4e2`.
+
+## Date
+
+2026-09-06
+
+## Context
+
+The integrated product exposed one reviewed unified Plugin workspace at
+`/plugins` through a standalone Code sidebar entry. Project Configuration no
+longer contained its predecessor Plugin Services sheet. The user first directed
+that Plugins belong in Project Settings, then clarified that the workspace must
+live on the same project page used to configure Agents and Skills rather than
+replace that page after navigation.
+
+The navigation change must not collapse the existing independent lifecycles for
+Marketplace acquisition, device installation, project enablement, Agent Skill
+assignment, runtime authorization, and billing. It also must not restore the
+retired duplicate sheet or move Main-owned Plugin authority into Renderer code.
+
+## Decision
+
+- The Agent/Skill Project Configuration page is the visible owner of the single
+  unified Plugin workspace.
+- Its `插件` resource card opens the workspace in a wide same-page drawer. The
+  Project Configuration page remains mounted behind it.
+- `/project-config/plugins` is the canonical deep link for the drawer-open state;
+  it renders Project Configuration rather than a standalone Plugin page.
+- `/plugins` preserves query and navigation state while redirecting to the
+  canonical URL. `/plugin-marketplace`, `/my-plugins`, and `/project-plugins`
+  remain deterministic filtered compatibility redirects.
+- The Code sidebar has no standalone Plugin entry.
+- The canonical workspace remains accessible before Code Provider initialization
+  and when no project is active, so Marketplace and account/device views do not
+  incorrectly depend on local project selection.
+- The existing unified controller, data sources, mutation semantics,
+  authentication, and lifecycle separation remain unchanged.
+
+## Rationale
+
+Plugin installation and activation configure resources that projects may use, so
+Project Configuration is the clearer navigation owner. Reusing the unified
+workspace avoids competing product surfaces and preserves one authoritative view
+across Marketplace, Account Library, device packages, and project status.
+Compatibility redirects protect existing deep links and authenticated return
+flows while establishing an unambiguous canonical location.
+
+## Consequences
+
+- Project Configuration gains a Plugin card beside models, Skills, and knowledge,
+  with access retained in the no-active-project state.
+- Closing the Plugin drawer returns to the already-mounted Project Configuration
+  page; Agent assignment actions close the drawer to expose that same page.
+- Existing bookmarks continue to work, but tests and new product links should use
+  `/project-config/plugins`.
+- Canonical project memory that names the Code sidebar or `/plugins` as the sole
+  current entry must be superseded during Integration Mode.
+- No backend contract, package trust boundary, runtime permission, billing rule,
+  or native Web Search behavior changes.
+
+## Supersedes
+
+- The navigation-only claim that the Code sidebar owns the single `插件` entry and
+  `/plugins` is the canonical product route.
+- It does not supersede the retirement of the duplicate Project Configuration
+  Plugin Services sheet; that implementation remains retired.
+
+## Evidence
+
+- User direction: “插件应该在项目设置中”, clarified as “是放在配置agent、skill那个项目页”.
+- Focused unit verification: 62/62 passed.
+- Electron Plugin journeys: 4/4 passed.
+- Full unit, typecheck, lint, and Vite production build passed.
+
+## Related
+
+- `.project-docs/10-decisions/adr-008-interactive-ai-app-scaffold.md`
+- `.project-docs/30-worklog/tasks/20260906-move-plugins-project-settings-7c91a4e2.md`
+- `src/pages/ProjectConfiguration/index.tsx`
+- `src/pages/Plugins/index.tsx`
+- `src/pages/Plugins/legacy-plugin-redirect.tsx`