Improve ACPX adapter configuration (#5290)

## Thinking Path

> - Paperclip orchestrates AI agents across several adapter
implementations.
> - ACPX is a local adapter path that can proxy Claude and Codex-style
execution.
> - Its configuration needed stronger schema defaults, provider-aware
model handling, and better UI support.
> - Plugin authors also need clear docs for managed resources.
> - This pull request improves ACPX adapter configuration and documents
plugin-managed resources.
> - The benefit is a more predictable adapter setup path without
changing unrelated control-plane behavior.

## What Changed

- Improved ACPX config schema, execution config handling, UI build
config, and route coverage.
- Added ACPX model filtering support and tests.
- Updated the agent config form and storybook coverage for ACPX
model/provider behavior.
- Expanded plugin authoring documentation for managed resources.

## Verification

- `pnpm install --frozen-lockfile`
- `pnpm exec vitest run server/src/__tests__/acpx-local-execute.test.ts
server/src/__tests__/adapter-routes.test.ts
ui/src/lib/acpx-model-filter.test.ts`

## Risks

- Low-to-medium risk: adapter configuration behavior changes can affect
ACPX users, but the change is isolated to ACPX/plugin-doc surfaces and
covered by targeted adapter tests.

## Model Used

- OpenAI GPT-5 Codex via Paperclip `codex_local` adapter, with
shell/git/GitHub CLI tool use.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] If this change affects the UI, I have included before/after
screenshots
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

packages/adapters/acpx-local/src/ui/build-config.ts

@@ -5,6 +5,7 @@ import {
   DEFAULT_ACPX_LOCAL_NON_INTERACTIVE_PERMISSIONS,
   DEFAULT_ACPX_LOCAL_PERMISSION_MODE,
   DEFAULT_ACPX_LOCAL_TIMEOUT_SEC,
+  DEFAULT_ACPX_LOCAL_WARM_HANDLE_IDLE_MS,
 } from "../index.js";
 
 function parseCommaArgs(value: string): string[] {
@@ -80,13 +81,15 @@ function readNumber(value: unknown, fallback: number): number {
 
 export function buildAcpxLocalConfig(v: CreateConfigValues): Record<string, unknown> {
   const schemaValues = v.adapterSchemaValues ?? {};
+  const agent = String(schemaValues.agent || DEFAULT_ACPX_LOCAL_AGENT);
   const ac: Record<string, unknown> = {
-    agent: schemaValues.agent || DEFAULT_ACPX_LOCAL_AGENT,
+    agent,
     mode: schemaValues.mode || DEFAULT_ACPX_LOCAL_MODE,
     permissionMode: schemaValues.permissionMode || DEFAULT_ACPX_LOCAL_PERMISSION_MODE,
     nonInteractivePermissions:
       schemaValues.nonInteractivePermissions || DEFAULT_ACPX_LOCAL_NON_INTERACTIVE_PERMISSIONS,
     timeoutSec: readNumber(schemaValues.timeoutSec, DEFAULT_ACPX_LOCAL_TIMEOUT_SEC),
+    warmHandleIdleMs: readNumber(schemaValues.warmHandleIdleMs, DEFAULT_ACPX_LOCAL_WARM_HANDLE_IDLE_MS),
   };
 
   for (const key of [
@@ -105,6 +108,11 @@ export function buildAcpxLocalConfig(v: CreateConfigValues): Record<string, unkn
   if (!ac.instructionsFilePath && v.instructionsFilePath) ac.instructionsFilePath = v.instructionsFilePath;
   if (!ac.promptTemplate && v.promptTemplate) ac.promptTemplate = v.promptTemplate;
   if (!ac.bootstrapPromptTemplate && v.bootstrapPrompt) ac.bootstrapPromptTemplate = v.bootstrapPrompt;
+  if (v.model?.trim()) ac.model = v.model.trim();
+  if (v.thinkingEffort) {
+    ac[agent === "codex" ? "modelReasoningEffort" : "effort"] = v.thinkingEffort;
+  }
+  if (schemaValues.fastMode === true) ac.fastMode = true;
 
   const env = parseEnvBindings(v.envBindings);
   const legacy = parseEnvVars(v.envVars);