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/BashTool/shouldUseSandbox.ts

@@ -19,34 +19,43 @@ type SandboxInput = {
 // It is not a security bug to be able to bypass excludedCommands — the sandbox permission
 // system (which prompts users) is the actual security control.
 function containsExcludedCommand(command: string): boolean {
-  // Check dynamic config for disabled commands and substrings (only for ants)
-  if (process.env.USER_TYPE === 'ant') {
-    const disabledCommands = getFeatureValue_CACHED_MAY_BE_STALE<{
-      commands: string[]
-      substrings: string[]
-    }>('tengu_sandbox_disabled_commands', { commands: [], substrings: [] })
+  // Check dynamic config for disabled commands and substrings
+  const raw = getFeatureValue_CACHED_MAY_BE_STALE<{
+    commands: string[]
+    substrings: string[]
+  }>('tengu_sandbox_disabled_commands', { commands: [], substrings: [] })
 
-    // Check if command contains any disabled substrings
-    for (const substring of disabledCommands.substrings) {
-      if (command.includes(substring)) {
+  const disabledCommands =
+    typeof raw === 'object' && raw !== null
+      ? raw
+      : { commands: [], substrings: [] }
+  const substrings = Array.isArray(disabledCommands.substrings)
+    ? disabledCommands.substrings
+    : []
+  const commands = Array.isArray(disabledCommands.commands)
+    ? disabledCommands.commands
+    : []
+
+  // Check if command contains any disabled substrings
+  for (const substring of substrings) {
+    if (command.includes(substring)) {
+      return true
+    }
+  }
+
+  // Check if command starts with any disabled commands
+  try {
+    const commandParts = splitCommand_DEPRECATED(command)
+    for (const part of commandParts) {
+      const baseCommand = part.trim().split(' ')[0]
+      if (baseCommand && commands.includes(baseCommand)) {
         return true
       }
     }
-
-    // Check if command starts with any disabled commands
-    try {
-      const commandParts = splitCommand_DEPRECATED(command)
-      for (const part of commandParts) {
-        const baseCommand = part.trim().split(' ')[0]
-        if (baseCommand && disabledCommands.commands.includes(baseCommand)) {
-          return true
-        }
-      }
-    } catch {
-      // If we can't parse the command (e.g., malformed bash syntax),
-      // treat it as not excluded to allow other validation checks to handle it
-      // This prevents crashes when rendering tool use messages
-    }
+  } catch {
+    // If we can't parse the command (e.g., malformed bash syntax),
+    // treat it as not excluded to allow other validation checks to handle it
+    // This prevents crashes when rendering tool use messages
   }
 
   // Check user-configured excluded commands from settings