Extract adapter registry across CLI, server, and UI

Refactor monolithic heartbeat service, AgentConfigForm, and CLI
heartbeat-run into a proper adapter registry pattern. Each adapter
type (process, claude-local, codex-local, http) gets its own module
with server-side execution logic, CLI invocation, and UI config form.
Significantly reduces file sizes and enables adding new adapters
without touching core code.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/adapters/process/index.ts

@@ -0,0 +1,12 @@
+import type { UIAdapterModule } from "../types";
+import { parseProcessStdoutLine } from "./parse-stdout";
+import { ProcessConfigFields } from "./config-fields";
+import { buildProcessConfig } from "./build-config";
+
+export const processUIAdapter: UIAdapterModule = {
+  type: "process",
+  label: "Shell Process",
+  parseStdoutLine: parseProcessStdoutLine,
+  ConfigFields: ProcessConfigFields,
+  buildAdapterConfig: buildProcessConfig,
+};