P4: SFTP provider, connection store, connection manager UI

- SftpProvider (ssh2): password + key auth, keepalive, clean-dispose vs
  unexpected-close distinction, POSIX path helpers, s->ms attr normalization
- ConnectionStore: plain JSON at appDataDir, 0600, atomic writes, folders
- connect/disconnect + store CRUD handlers; sessionClosed push -> panels fall
  back to local and in-flight jobs fail
- UI: session dropdown per panel (local/saved connections/manage), disconnect
  button, connection manager modal (folders, edit form, save/connect)
- electrobun bundler: external cpu-features/*.node (ssh2 optional natives)
- RpcService: gate requests on RPC socket open; defer initial panel loads past
  first render
- verified against 192.168.10.122: full op matrix, upload/download/remote-remote
  recursive transfers, roundtrip integrity, recursive remote delete, store CRUD

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/bun/rpc-handlers.ts

@@ -2,6 +2,8 @@ import { BrowserView } from "electrobun/bun";
 import type { AppRPC } from "../shared/rpc";
 import type { Result } from "../shared/types";
 import type { SessionRegistry } from "./fs/registry";
+import { SftpProvider } from "./fs/sftp";
+import type { ConnectionStore } from "./store/connections";
 import type { TransferEngine } from "./transfers/engine";
 import { removeRecursive } from "./transfers/walk";
 
@@ -9,6 +11,14 @@ import { removeRecursive } from "./transfers/walk";
 // default would cut them off.
 const MAX_REQUEST_TIME_MS = 10 * 60_000;
 
+export interface AppDeps {
+	registry: SessionRegistry;
+	engine: TransferEngine;
+	store: ConnectionStore;
+	/** Assigned after the rpc object exists (it needs rpc.send). */
+	events: { sessionClosed: (info: { sessionId: string; reason: string }) => void };
+}
+
 async function wrap<T extends object>(fn: () => Promise<T> | T): Promise<Result<T>> {
 	try {
 		return { ok: true, ...(await fn()) };
@@ -17,16 +27,37 @@ async function wrap<T extends object>(fn: () => Promise<T> | T): Promise<Result<
 	}
 }
 
-const NOT_YET = { ok: false as const, error: "Not implemented yet" };
-
-export function createAppRPC(registry: SessionRegistry, engine: TransferEngine) {
+export function createAppRPC({ registry, engine, store, events }: AppDeps) {
 	return BrowserView.defineRPC<AppRPC>({
 		maxRequestTime: MAX_REQUEST_TIME_MS,
 		handlers: {
 			requests: {
+				// ---- sessions ----
+				connect: ({ config }) =>
+					wrap(async () => {
+						let sessionId = "";
+						const provider = await SftpProvider.connect(config, (reason) => {
+							if (!sessionId) return;
+							registry.drop(sessionId);
+							engine.failSession(sessionId, reason);
+							events.sessionClosed({ sessionId, reason });
+						});
+						sessionId = registry.add(provider);
+						const homeDir = await provider.homeDir();
+						console.log(`[rpc] connected ${sessionId} -> ${config.username}@${config.host}`);
+						return { sessionId, homeDir };
+					}),
+
+				disconnect: ({ sessionId }) =>
+					wrap(async () => {
+						await registry.remove(sessionId);
+						console.log(`[rpc] disconnected ${sessionId}`);
+						return {};
+					}),
+
+				// ---- filesystem ----
 				listDir: ({ sessionId, path }) =>
 					wrap(async () => {
-						console.log(`[rpc] listDir ${sessionId} ${path ?? "(home)"}`);
 						const fs = registry.get(sessionId);
 						const dir = fs.normalize(path ?? (await fs.homeDir()));
 						return { path: dir, entries: await fs.list(dir) };
@@ -68,10 +99,7 @@ export function createAppRPC(registry: SessionRegistry, engine: TransferEngine)
 						return {};
 					}),
 
-				// P4: SFTP sessions
-				connect: async () => NOT_YET,
-				disconnect: async () => NOT_YET,
-
+				// ---- transfers ----
 				enqueueTransfers: (params) =>
 					wrap(async () => ({ jobIds: engine.enqueue(params) })),
 
@@ -86,12 +114,27 @@ export function createAppRPC(registry: SessionRegistry, engine: TransferEngine)
 						engine.dismiss(jobId);
 						return {};
 					}),
-				// P4: connection store
-				getConnections: async () => NOT_YET,
-				upsertConnection: async () => NOT_YET,
-				deleteConnection: async () => NOT_YET,
-				upsertFolder: async () => NOT_YET,
-				deleteFolder: async () => NOT_YET,
+
+				// ---- connection store ----
+				getConnections: () => wrap(async () => ({ store: await store.load() })),
+
+				upsertConnection: ({ connection }) =>
+					wrap(async () => ({ id: await store.upsertConnection(connection) })),
+
+				deleteConnection: ({ id }) =>
+					wrap(async () => {
+						await store.deleteConnection(id);
+						return {};
+					}),
+
+				upsertFolder: ({ folder }) =>
+					wrap(async () => ({ id: await store.upsertFolder(folder) })),
+
+				deleteFolder: ({ id }) =>
+					wrap(async () => {
+						await store.deleteFolder(id);
+						return {};
+					}),
 			},
 		},
 	});