Name agents by their first prompt line instead of an LLM summary (#1563)

* Name agents by their first prompt line instead of an LLM summary

The workspace title already captures the task; the LLM-generated agent
title just restated the same prompt. Drop the generator and keep the
provisional title (first prompt line), so the agent label stays
deterministic and explicit titles still win.

* Remove the no-op agent-title setting and leftover generator plumbing

Deleting the agent-title generator left its whole surface dangling: a
configurable "Agent titles" project setting that no longer did anything,
dead create-path plumbing, generator-only import/MCP deps, and the mock
provider's agent-title parser. Remove all of it, plus a dead test mock
and timing sleeps that guarded the deleted background job. Replace them
with a no-mock lifecycle test asserting the title stays the first prompt
line across create and settle.

Old paseo.json files with metadataGeneration.agentTitle still parse via
schema passthrough — see COMPAT(projectMetadataAgentTitle).

packages/app/src/utils/project-config-form.ts

@@ -7,12 +7,7 @@ import type {
 
 export type LifecycleOriginalKind = "string" | "array" | "missing";
 
-export const METADATA_PROMPT_KEYS = [
-  "agentTitle",
-  "branchName",
-  "commitMessage",
-  "pullRequest",
-] as const;
+export const METADATA_PROMPT_KEYS = ["branchName", "commitMessage", "pullRequest"] as const;
 export type MetadataPromptKey = (typeof METADATA_PROMPT_KEYS)[number];
 
 export interface ProjectScriptDraft {
@@ -105,7 +100,6 @@ function nextScriptDraftId(): string {
 
 function emptyMetadataPrompts(): Record<MetadataPromptKey, string> {
   return {
-    agentTitle: "",
     branchName: "",
     commitMessage: "",
     pullRequest: "",