P1: typed RPC bridge + FileSystemProvider + dual-panel local browsing

- shared/types + shared/rpc: full wire contract (Result envelope, no exceptions cross the bridge)
- FileSystemProvider interface, LocalProvider, SessionRegistry with built-in 'local'
- walk.ts: provider-generic recursive walk + removeRecursive
- rpc-handlers wired into BrowserWindow; 10min request timeout for slow SFTP ops
- Angular: RpcService (Electroview bridge + plain-browser guard), PanelsService with
  signals-based PanelState (sort/cursor/selection), FilePanel component with
  keyboard nav (arrows/Space/Enter/Backspace/Tab), path bar, toasts
- verified: both panels listDir home over the bridge in the running app

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

src/bun/rpc-handlers.ts

@@ -0,0 +1,86 @@
+import { BrowserView } from "electrobun/bun";
+import type { AppRPC } from "../shared/rpc";
+import type { Result } from "../shared/types";
+import type { SessionRegistry } from "./fs/registry";
+import { removeRecursive } from "./transfers/walk";
+
+// SFTP ops can be slow (big listings, recursive deletes) — the 1s electrobun
+// default would cut them off.
+const MAX_REQUEST_TIME_MS = 10 * 60_000;
+
+async function wrap<T extends object>(fn: () => Promise<T> | T): Promise<Result<T>> {
+	try {
+		return { ok: true, ...(await fn()) };
+	} catch (error) {
+		return { ok: false, error: error instanceof Error ? error.message : String(error) };
+	}
+}
+
+const NOT_YET = { ok: false as const, error: "Not implemented yet" };
+
+export function createAppRPC(registry: SessionRegistry) {
+	return BrowserView.defineRPC<AppRPC>({
+		maxRequestTime: MAX_REQUEST_TIME_MS,
+		handlers: {
+			requests: {
+				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) };
+					}),
+
+				mkdir: ({ sessionId, path }) =>
+					wrap(async () => {
+						await registry.get(sessionId).mkdir(path);
+						return {};
+					}),
+
+				createFile: ({ sessionId, path }) =>
+					wrap(async () => {
+						await registry.get(sessionId).createEmptyFile(path);
+						return {};
+					}),
+
+				rename: ({ sessionId, oldPath, newPath }) =>
+					wrap(async () => {
+						await registry.get(sessionId).rename(oldPath, newPath);
+						return {};
+					}),
+
+				deleteEntries: ({ sessionId, entries }) =>
+					wrap(async () => {
+						const fs = registry.get(sessionId);
+						for (const { path, type } of entries) {
+							await removeRecursive(fs, path, type);
+						}
+						return {};
+					}),
+
+				chmod: ({ sessionId, paths, mode }) =>
+					wrap(async () => {
+						const fs = registry.get(sessionId);
+						for (const path of paths) {
+							await fs.chmod(path, mode);
+						}
+						return {};
+					}),
+
+				// P4: SFTP sessions
+				connect: async () => NOT_YET,
+				disconnect: async () => NOT_YET,
+				// P3: transfer engine
+				enqueueTransfers: async () => NOT_YET,
+				cancelTransfer: async () => NOT_YET,
+				dismissTransfer: async () => NOT_YET,
+				// P4: connection store
+				getConnections: async () => NOT_YET,
+				upsertConnection: async () => NOT_YET,
+				deleteConnection: async () => NOT_YET,
+				upsertFolder: async () => NOT_YET,
+				deleteFolder: async () => NOT_YET,
+			},
+		},
+	});
+}