feat(cli): add global option to disable automatic session title changes

[chenbojian]

Summary

• Adds enableAutoTitle setting in ~/.hapi/settings.json (defaults to true)
• When set to false, the title instruction is omitted from system prompts (Claude, Codex, OpenCode) and the change_title MCP tool is not registered
• No changes to launcher files or web frontend — minimal, self-contained change

Support part of #271

Test plan

• Set "enableAutoTitle": false in ~/.hapi/settings.json → start a session → verify no title-change tool calls and no title instruction in prompt
• Remove setting or set true → verify behavior unchanged
• Run bun run typecheck in cli/ — passes
• Run bunx vitest run src/claude/utils/claudeSettings.test.ts — all 11 tests pass

[github-actions]

Review mode: initial

Findings

• [Major] enableAutoTitle=false does not fully disable automatic title changes outside Claude. The new guard removes the HTTP-side tool in cli/src/claude/utils/startHappyServer.ts:45, but Codex/OpenCode still launch the shared stdio bridge, and that bridge still unconditionally advertises change_title in cli/src/codex/happyMcpStdioBridge.ts:72. That leaves the tool visible and callable in the non-Claude modes this PR claims to cover.

Summary

• enableAutoTitle=false currently suppresses prompt text, but not end-to-end tool exposure for Codex/OpenCode.
• Not found in tests: coverage for the MCP bridge/tool advertisement path when enableAutoTitle is false.

Testing

• Not run (automation)

HAPI Bot

[github-actions]

[MAJOR] enableAutoTitle=false only removes the tool from the HTTP MCP server here. Codex and OpenCode still go through buildHapiMcpBridge(...), and cli/src/codex/happyMcpStdioBridge.ts:72 still unconditionally re-registers change_title, so those modes can still see and call the title tool.

Suggested fix:

const client = await ensureHttpClient();
const { tools } = await client.listTools();

if (tools.some((tool) => tool.name === 'change_title')) {
    server.registerTool<any, any>('change_title', {
        description: 'Change the title of the current chat session',
        title: 'Change Chat Title',
        inputSchema: changeTitleInputSchema,
    }, async (args: Record<string, unknown>) => {
        return client.callTool({ name: 'change_title', arguments: args });
    });
}

[chenbojian]

fixed in next commit

[github-actions]

Findings

• No actionable findings in the updated diff.

Summary

• Review mode: follow-up after new commits
• No new diff-attributable correctness, security, or maintainability issues found.
• Residual risk: not found in repo/docs/tests, targeted coverage for enableAutoTitle=false through the non-Claude launch paths touched here, especially cli/src/codex/happyMcpStdioBridge.ts:68, cli/src/opencode/opencodeLocalLauncher.ts:274, and cli/src/opencode/opencodeRemoteLauncher.ts:120.

Testing

• Not run (automation)

HAPI Bot

[github-actions]

Findings

• [Major] Disabling auto title still clears Codex developer instructions — cli/src/codex/utils/systemPrompt.ts:11 now represents the disabled state as '', but the existing Codex launch/config paths still pass that value as an explicit override (cli/src/codex/codexLocal.ts:74, cli/src/codex/utils/appServerConfig.ts:86). For a user who sets enableAutoTitle=false, HAPI will send developer_instructions="" instead of omitting only the HAPI title prompt, which can wipe their Codex-level developer instructions/config for the session.
  Suggested fix:

  // cli/src/codex/codexLocal.ts
  if (codexSystemPrompt) {
      args.push(...buildDeveloperInstructionsArg(codexSystemPrompt));
  }
  
  // cli/src/codex/utils/appServerConfig.ts
  const developerInstructions = [baseInstructions, args.developerInstructions]
      .filter(Boolean)
      .join('\n\n');
  
  const configWithInstructions = {
      ...config,
      ...(developerInstructions ? { developer_instructions: developerInstructions } : {}),
      ...(args.mode.modelReasoningEffort ? { model_reasoning_effort: args.mode.modelReasoningEffort } : {})
  };

Summary

• Review mode: follow-up after new commits
• One correctness regression found in the Codex disabled-auto-title path.
• Residual risk: no end-to-end coverage found for enableAutoTitle=false across Codex/OpenCode launchers.

Testing

• Not run (automation: bun/bunx not found in PATH)

HAPI Bot

[github-actions]

[MAJOR] When enableAutoTitle=false, this exports an empty string, but the Codex launch/config paths still send that as an explicit developer_instructions="" override (codexLocal.ts:74, appServerConfig.ts:86). That disables more than the HAPI title prompt: it can clear a user's Codex developer instructions/config for the session. Omit the override when the HAPI prompt is empty.

Suggested fix:

// cli/src/codex/codexLocal.ts
if (codexSystemPrompt) {
    args.push(...buildDeveloperInstructionsArg(codexSystemPrompt));
}

// cli/src/codex/utils/appServerConfig.ts
const developerInstructions = [baseInstructions, args.developerInstructions]
    .filter(Boolean)
    .join('\n\n');

const configWithInstructions = {
    ...config,
    ...(developerInstructions ? { developer_instructions: developerInstructions } : {}),
    ...(args.mode.modelReasoningEffort ? { model_reasoning_effort: args.mode.modelReasoningEffort } : {})
};