coder(providers): v2.3 provider-lifecycle phase 3 — generic ACP dispatch

ACP dispatch now spawns from the resolved registry's launch spec instead of a hardcoded per-name switch. acp-spawn.ts gains resolveLaunchSpec(resolved, installPath): launchCommand (config override / custom-ACP command) wins, else the kept resolveAcpSpawnArgs switch is the built-in fallback. acp-dispatch.ts spawns spec.binary/spec.args with env { ...process.env, ...spec.env }; dispatcher.ts loads the resolved def by task.agent and passes it through. Config-defined custom ACP providers dispatch with no new switch case. Built-in dispatch (opencode/goose/qwen) is byte-identical to pre-v2.3 — proven by a regression test (opencode->['acp'], goose->['acp'], qwen->['--acp'], binary=installPath ?? id, empty env -> plain process.env). Deliberate deviation from design's !installPath->null: the installPath ?? id fallback is preserved. setSessionMode/permission/streaming and the dispatcher poll/NOTIFY/running-guard untouched. 7 new acp-spawn.test.ts cases. No routes/UI (Phase 4+).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/coder/src/services/dispatcher.ts

@@ -5,6 +5,7 @@ import type { WsFrame } from '@boocode/server/ws-frames';
 import type { Config } from '../config.js';
 import { createWorktree, diffWorktree, cleanupWorktree } from './worktrees.js';
 import { dispatchViaAcp } from './acp-dispatch.js';
+import { getResolvedRegistry } from './provider-config-registry.js';
 import { dispatchViaPty } from './pty-dispatch.js';
 import { clearTaskCommands, setTaskCommands } from './agent-commands-cache.js';
 import { getManifestCommands } from './provider-commands.js';
@@ -340,6 +341,7 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
       if (supportsAcp) {
         const result = await dispatchViaAcp({
           agent,
+          resolved: getResolvedRegistry().get(agent),
           task: task.input,
           worktreePath,
           installPath: installPath ?? undefined,