refactor: separate core plugins and desktop shell

Cargo.toml

@@ -8,6 +8,7 @@ resolver = "2"
 members = [
     "crates/kernel",
     "crates/core",
+    "crates/plugins",
     "crates/tui",
     "crates/server",
     "apps/desktop/src-host",
@@ -32,6 +33,7 @@ tracing = "0.1"
 # Local crates
 codetwo-kernel = { path = "crates/kernel" }
 codetwo-core = { path = "crates/core" }
+codetwo-plugins = { path = "crates/plugins" }
 
 [patch.crates-io]
 # 0.2.1 links Ghostty's Windows static archive under the Unix library name. Keep the published

README.md

@@ -40,8 +40,8 @@ whole turn, and only then send it to the agent you choose.
 - **Git-aware execution.** Use per-session worktrees, automatic checkpoints, diffs, revert, and
   explicit commit/push flows.
 - **Three surfaces.** C2 ships an Electrobun desktop app, a ratatui TUI, and a paired remote web
-  client. All three use the same Rust core and Plugin Kernel; Electrobun is the desktop shell and
-  relays one command/event protocol to its bundled Rust host.
+  client. All three compose the same Rust Core through the same plugin runtime; Electrobun is the
+  desktop shell and relays one command/event protocol to its bundled Rust host.
 
 ## How it fits together
 
@@ -50,7 +50,9 @@ Claude Code · Codex · Grok · Cursor · OpenCode 1 · OpenCode 2 · Pi · Kimi
                               │
                          ACP over stdio
                               │
-                 Rust core + plugin kernel
+                 Rust product core
+                         │
+               Plugin composition layer
                     ┌─────────┼─────────┐
                     │         │         │
                 Desktop      TUI      Remote
@@ -150,7 +152,8 @@ tailnet; C2 does not provide a hosted relay.
 | Path                             | Purpose                                                                     |
 | -------------------------------- | --------------------------------------------------------------------------- |
 | [`crates/kernel`](crates/kernel) | Reactive plugin runtime and command registry                                |
-| [`crates/core`](crates/core)     | ACP engine, sessions, providers, memory, git, terminal, browser, and skills |
+| [`crates/core`](crates/core)     | Plugin-independent product domain: ACP, sessions, providers, policy, and persistence |
+| [`crates/plugins`](crates/plugins) | Core adapters, built-in runtime graph, extension bundles, protocol, and marketplace |
 | [`crates/tui`](crates/tui)       | ratatui frontend                                                            |
 | [`crates/server`](crates/server) | Headless server, pairing, WebSocket protocol, and remote client             |
 | [`apps/desktop`](apps/desktop)   | Electrobun + React + BlockNote desktop app                                  |

apps/desktop/src-host/Cargo.toml

@@ -4,7 +4,7 @@ version.workspace = true
 edition.workspace = true
 license.workspace = true
 rust-version.workspace = true
-description = "C2 native sidecar — a JSON-lines bridge over codetwo-core."
+description = "C2 native sidecar — a JSON-lines desktop container over CoreApp."
 
 [dependencies]
 serde.workspace = true
@@ -14,6 +14,7 @@ uuid.workspace = true
 blake3 = "1"
 codetwo-core.workspace = true
 codetwo-kernel.workspace = true
+codetwo-plugins.workspace = true
 codetwo-server = { path = "../../../crates/server" }
 futures-util = "0.3"
 reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls", "stream"] }

apps/desktop/src-host/src/automation.rs

@@ -7,7 +7,6 @@
 use std::sync::Arc;
 use std::time::Duration;
 
-use codetwo_core::app::{EngineService, EventBus, StoreService};
 use codetwo_core::permission::ExecutionPolicy;
 use codetwo_core::session::SessionRunState;
 use codetwo_core::skill::DocBlock;
@@ -18,6 +17,7 @@ use codetwo_core::{
 use codetwo_kernel::{
     async_trait, Context, Injection, Plugin, PluginError, PluginResult, WeakContext,
 };
+use codetwo_plugins::{EngineService, EventBus, StoreService};
 use serde::Deserialize;
 use serde_json::Value;
 use tokio::sync::broadcast;

apps/desktop/src-host/src/device_sync.rs

@@ -9,13 +9,13 @@ use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
-use codetwo_core::app::StoreService;
 use codetwo_core::device_sync::{
     device_sync_snapshot_version, merge_device_sync_documents, DeviceSyncCounts, DeviceSyncDocument,
 };
 use codetwo_core::session::now_millis;
 use codetwo_core::Store;
 use codetwo_kernel::{async_trait, Context, Injection, Plugin, PluginError, PluginResult, Service};
+use codetwo_plugins::StoreService;
 use futures_util::future::join_all;
 use reqwest::{Client, Response, Url};
 use serde::de::DeserializeOwned;

apps/desktop/src-host/src/host_events.rs

@@ -1,10 +1,10 @@
 //! Scope-owned forwarding from core broadcasts to the desktop host protocol.
 
-use codetwo_core::app::events::PluginsChanged;
-use codetwo_core::app::{EventBus, TerminalEvent, TerminalOutputEvent};
 use codetwo_kernel::{
     async_trait, CommandRealm, Context, Injection, Plugin, PluginError, PluginResult,
 };
+use codetwo_plugins::events::PluginsChanged;
+use codetwo_plugins::{EventBus, TerminalEvent, TerminalOutputEvent};
 use serde::Serialize;
 use serde_json::Value;
 use tokio::sync::broadcast;

apps/desktop/src-host/src/lib.rs

@@ -17,12 +17,12 @@ mod scene_mcp;
 use std::path::PathBuf;
 use std::sync::Arc;
 
-use codetwo_core::app::plugins::{EngineInputs, EnginePlugin};
-use codetwo_core::app::{AppConfig, CoreApp};
 use codetwo_core::{CanvasFeatureGate, DesktopMcpConfig, Engine};
 use codetwo_kernel::{
     PluginCategory, PluginEntry, PluginMetadata, PluginOrigin, PluginRole, PluginScopeSupport,
 };
+use codetwo_plugins::builtins::{EngineInputs, EnginePlugin};
+use codetwo_plugins::{AppConfig, CoreApp};
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
 use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
@@ -152,7 +152,7 @@ pub async fn run() -> Result<(), String> {
         browser_enabled: false,
     };
 
-    let mut registry = codetwo_core::app::plugins::builtin_registry();
+    let mut registry = codetwo_plugins::builtins::builtin_registry();
     #[cfg(unix)]
     let engine_metadata = registry
         .get("engine")

apps/desktop/src-host/src/lsp.rs

@@ -12,9 +12,9 @@ use std::process::{Child, ChildStdin, ChildStdout, Command, Stdio};
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex, MutexGuard};
 
-use codetwo_core::app::events::PluginsChanged;
-use codetwo_core::app::Paths;
 use codetwo_kernel::{async_trait, Context, Injection, Plugin, PluginError, PluginResult};
+use codetwo_plugins::events::PluginsChanged;
+use codetwo_plugins::Paths;
 use serde::Deserialize;
 use serde::Serialize;
 use serde_json::Value;
@@ -87,7 +87,7 @@ fn lsp_start(
     state.ensure_open()?;
     let plugins_dir = paths.plugins();
     if plugins_dir.is_dir() {
-        let plugins = codetwo_core::plugin::load_dir(&plugins_dir).unwrap_or_default();
+        let plugins = codetwo_plugins::bundle::load_dir(&plugins_dir).unwrap_or_default();
         for plugin in plugins
             .into_iter()
             .filter(|plugin| plugin.enabled && plugin.trusted)

apps/desktop/src-host/src/remote.rs

@@ -6,9 +6,9 @@
 use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 
-use codetwo_core::app::{CanvasService, EngineService, EventBus, StoreService};
 use codetwo_core::{Engine, Event, Store};
 use codetwo_kernel::{async_trait, Context, Injection, Plugin, PluginError, PluginResult};
+use codetwo_plugins::{CanvasService, EngineService, EventBus, StoreService};
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
 use tokio::sync::broadcast;
@@ -230,8 +230,7 @@ impl Plugin for RemotePlugin {
     }
 
     fn inject(&self) -> Injection {
-        Injection::required(["engine", "store", "bus", "canvas"])
-            .with_optional(["device-sync"])
+        Injection::required(["engine", "store", "bus", "canvas"]).with_optional(["device-sync"])
     }
 
     fn description(&self) -> Option<&str> {
@@ -295,9 +294,10 @@ impl Plugin for RemotePlugin {
                 let auth = Arc::new(codetwo_server::AuthState::load(Some(
                     service.auth_path.clone(),
                 )));
-                let device_sync_http = service.device_sync.clone().map(|device_sync| {
-                    device_sync as Arc<dyn codetwo_server::DeviceSyncHttp>
-                });
+                let device_sync_http = service
+                    .device_sync
+                    .clone()
+                    .map(|device_sync| device_sync as Arc<dyn codetwo_server::DeviceSyncHttp>);
                 let bound = codetwo_server::bind_and_serve_with_services(
                     service.engine.clone(),
                     service.events.clone(),
@@ -481,9 +481,7 @@ impl Plugin for RemotePlugin {
                     true
                 } else {
                     match &service.device_sync {
-                        Some(sync) => sync
-                            .revoke_device(&args.id)
-                            .map_err(PluginError::new)?,
+                        Some(sync) => sync.revoke_device(&args.id).map_err(PluginError::new)?,
                         None => false,
                     }
                 };

apps/desktop/src-host/src/scene_mcp.rs

@@ -2,7 +2,7 @@
 
 use std::io::{BufRead, BufReader, Write};
 
-use codetwo_core::app::{CoreApp, SceneService, StoreService};
+use codetwo_plugins::{CoreApp, SceneService, StoreService};
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
 

apps/desktop/src/App.tsx

@@ -234,6 +234,7 @@ import { RemoteModal } from "./remote/Remote";
 import { IssuesModal } from "./issues/Issues";
 import { PreviewModal } from "./editor/Preview";
 import { FileBrowserModal } from "./files/FileBrowser";
+import { FileDockContent } from "./files/FileDockContent";
 import { WorkspaceSearchModal } from "./files/WorkspaceSearch";
 import type { FileRevealTarget } from "./files/FileViewer";
 import { dirtyKey, isDirty as isFileDirty, markDirty } from "./files/dirty";
@@ -380,6 +381,10 @@ import {
   type DockSurface,
   type DockTab,
 } from "./dock/Dock";
+import { BrowserPanel } from "./browser/Browser";
+import { GitDockContent } from "./git/GitDockContent";
+import { TerminalDockContent } from "./terminal/TerminalDockContent";
+import { TrajectoryView } from "./session/TrajectoryView";
 import { SessionRail } from "./sidebar/SessionRail";
 import { EnvironmentPopover } from "./environment/EnvironmentPopover";
 import { MissionControlDialog } from "./sidebar/MissionControl.tsx";
@@ -7768,12 +7773,11 @@ export default function App() {
             <div className="flex h-full min-h-0 min-w-0 flex-col overflow-hidden">
           {/* Also a window drag region: the overlay title bar draws nothing to grab. Buttons and
               other children stay clickable — only elements carrying the attribute start a drag. */}
-          {/* The shared titlebar height centres the 28px controls on the same 48px line as the rail
-              and dock headers. With the rail collapsed, the inset clears
-              the traffic lights and the expand button takes the wordmark's place. */}
+          {/* The shared 40px title line keeps every pane on one baseline. With the rail collapsed,
+              the inset clears the traffic lights and the expand button takes the wordmark's place. */}
           <header
             className={cn(
-              "session-header electrobun-webkit-app-region-drag flex min-w-0 shrink-0 items-center gap-2 border-b py-2.5 pr-4",
+              "session-header window-titlebar electrobun-webkit-app-region-drag flex min-w-0 shrink-0 items-center gap-2 pr-4",
               displayedRailCollapsed ? "window-controls-safe-main" : "pl-4",
             )}
           >
@@ -8293,36 +8297,59 @@ export default function App() {
               }}
               onClose={() => manualDockTab(null)}
               autoTab={dockAutoHint?.surface ?? null}
-              highlightFile={dockAutoHint?.file ?? null}
-              cwd={cwd || null}
-              projectPath={
-                activeProject ? normalizePluginProjectPath(activeProject) : null
-              }
-              sessionKey={activeSession ?? "main"}
-              git={git}
-              onRefreshGit={refreshGit}
-              onOpenSourceControl={openSourceControl}
-              browserUrl={browserUrl}
-              onNavigate={setBrowserUrl}
-              onAnnotate={(n) => void annotate(n)}
-              onInsertFile={(p) => insertFileRef.current?.(p)}
-              onSendText={(text) => insertTextRef.current?.(text)}
-              onOpenFile={openFileTab}
-              openFiles={openFiles}
-              activeFile={activeFile}
-              fileReveal={fileReveal}
-              onActiveFile={(path) => {
-                setActiveFile(path);
-                setFileReveal(null);
+              content={{
+                trajectory: (
+                  <TrajectoryView
+                    turns={turns}
+                    usage={focusedSessionUsage}
+                    hasEarlier={focusedTranscriptState.nextBefore !== null}
+                    loadingEarlier={focusedTranscriptState.loadingEarlier}
+                    onLoadEarlier={() => void loadEarlierTranscript(paneLayout.focused)}
+                  />
+                ),
+                browser: (
+                  <BrowserPanel
+                    url={browserUrl}
+                    projectPath={lspProjectPath}
+                    visible={dockTab !== null}
+                    onNavigate={setBrowserUrl}
+                    onAnnotate={(notes) => void annotate(notes)}
+                  />
+                ),
+                terminal: (
+                  <TerminalDockContent
+                    cwd={cwd || null}
+                    projectPath={lspProjectPath}
+                    sessionKey={activeSession ?? "main"}
+                    onSendText={(text) => insertTextRef.current?.(text)}
+                  />
+                ),
+                files: (
+                  <FileDockContent
+                    cwd={cwd || null}
+                    openFiles={openFiles}
+                    activeFile={activeFile}
+                    reveal={fileReveal}
+                    highlightFile={dockAutoHint?.file ?? null}
+                    onActiveFile={(path) => {
+                      setActiveFile(path);
+                      setFileReveal(null);
+                    }}
+                    onCloseFile={closeFileTab}
+                    onInsertFile={(path) => insertFileRef.current?.(path)}
+                    onOpenFile={openFileTab}
+                    onSendText={(text) => insertTextRef.current?.(text)}
+                  />
+                ),
+                git: (
+                  <GitDockContent
+                    cwd={cwd || null}
+                    status={git}
+                    onRefresh={refreshGit}
+                    onOpenSourceControl={openSourceControl}
+                  />
+                ),
               }}
-              onCloseFile={closeFileTab}
-              turns={turns}
-              usage={sessionUsage}
-              hasEarlier={focusedTranscriptState.nextBefore !== null}
-              loadingEarlier={focusedTranscriptState.loadingEarlier}
-              onLoadEarlier={() =>
-                void loadEarlierTranscript(paneLayout.focused)
-              }
               width={dockWidth}
               onWidth={setDockWidth}
               reservedWidth={railInlineWidth}