feat: open useful USER_TYPE-gated features to all users (#644)

* feat: open useful USER_TYPE-gated features to all users

Remove 13 process.env.USER_TYPE === 'ant' gates that restricted useful
features to Anthropic employees. These features work without Anthropic
infrastructure and are now available to all open-build users.

Features opened:
- Agent nesting (sub-agents can spawn sub-agents)
- Effort 'max' persistence in settings
- Plan mode interview phase (controlled by feature flags)
- Sandbox disabled commands (via ~/.claude/feature-flags.json)
- All tips visible to all users (plan mode, feedback, shift-tab)

Simplified:
- Fullscreen defaults to off (use /config to enable)
- Explore agent always uses haiku model
- Plan mode tool uses conservative prompt for all users

Continues the USER_TYPE cleanup from #637 (dead code) and builds
on #639 (local feature flags).

* fix: address Copilot review comments — remove residual dead code

1. bridgeConfig.ts: ungate bridge override functions — return env vars
   directly instead of hardcoded undefined
2. bridgeMain.ts + initReplBridge.ts: ungate sessionIngressUrl — read
   CLAUDE_BRIDGE_SESSION_INGRESS_URL without USER_TYPE check
3. tools.ts: remove dead ConfigTool/TungstenTool imports, narrow
   eslint-disable scope, stub REPLTool/SuggestBackgroundPRTool to null
4. readOnlyValidation.ts: remove orphaned ANT_ONLY_COMMAND_ALLOWLIST
   and unused GH_READ_ONLY_COMMANDS import
5. insights.ts: remove entire remote collection plumbing (types,
   functions, options, display logic)
6. osc.ts: hardcode supportsTabStatus() to false (internal-only feature)
7. state.ts: simplify addSlowOperation/getSlowOperations to no-ops,
   remove dead constants

* fix: address Copilot review on PR #644

1. settings/types.ts: allow 'max' effort level for all users in Zod
   schema — was still gated behind USER_TYPE=ant, causing 'max' to be
   silently dropped on settings reload
2. shouldUseSandbox.ts: defensively normalize disabledCommands from
   feature flag config with Array.isArray() guards

* fix: address second round of Copilot review on PR #644

1. shouldUseSandbox.ts: validate top-level shape of disabledCommands
   before accessing properties (handles null/primitive from feature flag)
2. fullscreen.ts: update JSDoc to reflect removal of USER_TYPE default
3. osc.ts: update JSDoc — "Ant-only" → "Currently disabled"

src/tools.ts

@@ -12,16 +12,9 @@ import { WebFetchTool } from './tools/WebFetchTool/WebFetchTool.js'
 import { TaskStopTool } from './tools/TaskStopTool/TaskStopTool.js'
 import { BriefTool } from './tools/BriefTool/BriefTool.js'
 // Dead code elimination: conditional import for internal-only tools
-/* eslint-disable custom-rules/no-process-env-top-level, @typescript-eslint/no-require-imports */
-const REPLTool =
-  process.env.USER_TYPE === 'ant'
-    ? require('./tools/REPLTool/REPLTool.js').REPLTool
-    : null
-const SuggestBackgroundPRTool =
-  process.env.USER_TYPE === 'ant'
-    ? require('./tools/SuggestBackgroundPRTool/SuggestBackgroundPRTool.js')
-        .SuggestBackgroundPRTool
-    : null
+/* eslint-disable @typescript-eslint/no-require-imports */
+const REPLTool = null
+const SuggestBackgroundPRTool = null
 const SleepTool =
   feature('PROACTIVE') || feature('KAIROS')
     ? require('./tools/SleepTool/SleepTool.js').SleepTool
@@ -55,7 +48,6 @@ import { TodoWriteTool } from './tools/TodoWriteTool/TodoWriteTool.js'
 import { ExitPlanModeV2Tool } from './tools/ExitPlanModeTool/ExitPlanModeV2Tool.js'
 import { TestingPermissionTool } from './tools/testing/TestingPermissionTool.js'
 import { GrepTool } from './tools/GrepTool/GrepTool.js'
-import { TungstenTool } from './tools/TungstenTool/TungstenTool.js'
 // Lazy require to break circular dependency: tools.ts -> TeamCreateTool/TeamDeleteTool -> ... -> tools.ts
 /* eslint-disable @typescript-eslint/no-require-imports */
 const getTeamCreateTool = () =>
@@ -76,7 +68,6 @@ import { ToolSearchTool } from './tools/ToolSearchTool/ToolSearchTool.js'
 import { EnterPlanModeTool } from './tools/EnterPlanModeTool/EnterPlanModeTool.js'
 import { EnterWorktreeTool } from './tools/EnterWorktreeTool/EnterWorktreeTool.js'
 import { ExitWorktreeTool } from './tools/ExitWorktreeTool/ExitWorktreeTool.js'
-import { ConfigTool } from './tools/ConfigTool/ConfigTool.js'
 import { TaskCreateTool } from './tools/TaskCreateTool/TaskCreateTool.js'
 import { TaskGetTool } from './tools/TaskGetTool/TaskGetTool.js'
 import { TaskUpdateTool } from './tools/TaskUpdateTool/TaskUpdateTool.js'
@@ -209,8 +200,6 @@ export function getAllBaseTools(): Tools {
     AskUserQuestionTool,
     SkillTool,
     EnterPlanModeTool,
-    ...(process.env.USER_TYPE === 'ant' ? [ConfigTool] : []),
-    ...(process.env.USER_TYPE === 'ant' ? [TungstenTool] : []),
     ...(SuggestBackgroundPRTool ? [SuggestBackgroundPRTool] : []),
     ...(WebBrowserTool ? [WebBrowserTool] : []),
     ...(isTodoV2Enabled()