fix: remove cpulimit, use nice only for CPU priority

cpulimit -f interfered with Claude's Ink terminal UI causing duplicate
prompt rendering. Replaced with nice-only approach.

- Remove cpulimit entirely (was causing display issues)
- Rename CpuLimitConfig -> NiceConfig for clean naming
- Simplify wrapWithCpuLimit -> wrapWithNice
- Update UI labels and settings key (cpuLimit -> nice)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/web/public/app.js

@@ -4886,13 +4886,10 @@ class ClaudemanApp {
     claudeModeSelect.onchange = () => {
       allowedToolsRow.style.display = claudeModeSelect.value === 'allowedTools' ? '' : 'none';
     };
-    // CPU Limiting settings
-    const cpuLimitSettings = settings.cpuLimit || {};
-    document.getElementById('appSettingsCpuLimitEnabled').checked = cpuLimitSettings.enabled ?? false;
-    document.getElementById('appSettingsCpuNiceValue').value = cpuLimitSettings.niceValue ?? 10;
-    document.getElementById('appSettingsCpuLimitPercent').value = cpuLimitSettings.cpuLimitPercent ?? 80;
-    // Check cpulimit availability and update status indicator
-    this.checkCpulimitAvailability();
+    // CPU Priority settings
+    const niceSettings = settings.nice || {};
+    document.getElementById('appSettingsNiceEnabled').checked = niceSettings.enabled ?? false;
+    document.getElementById('appSettingsNiceValue').value = niceSettings.niceValue ?? 10;
     // Notification settings
     const notifPrefs = this.notificationManager?.preferences || {};
     document.getElementById('appSettingsNotifEnabled').checked = notifPrefs.enabled ?? true;
@@ -4954,12 +4951,10 @@ class ClaudemanApp {
       // Claude CLI settings
       claudeMode: document.getElementById('appSettingsClaudeMode').value,
       allowedTools: document.getElementById('appSettingsAllowedTools').value.trim(),
-      // CPU Limiting settings
-      cpuLimit: {
-        enabled: document.getElementById('appSettingsCpuLimitEnabled').checked,
-        niceValue: parseInt(document.getElementById('appSettingsCpuNiceValue').value) || 10,
-        cpuLimitPercent: parseInt(document.getElementById('appSettingsCpuLimitPercent').value) || 80,
-        useCpulimitIfAvailable: true,
+      // CPU Priority settings
+      nice: {
+        enabled: document.getElementById('appSettingsNiceEnabled').checked,
+        niceValue: parseInt(document.getElementById('appSettingsNiceValue').value) || 10,
       },
     };
 
@@ -5021,36 +5016,6 @@ class ClaudemanApp {
     return {};
   }
 
-  // Check if cpulimit is available and update the UI status indicator
-  async checkCpulimitAvailability() {
-    const statusEl = document.getElementById('cpuLimitStatus');
-    const percentInput = document.getElementById('appSettingsCpuLimitPercent');
-    if (!statusEl) return;
-
-    try {
-      const res = await fetch('/api/system/cpu-limit-status');
-      if (res.ok) {
-        const data = await res.json();
-        if (data.cpulimitAvailable) {
-          statusEl.textContent = '\u2713';  // Checkmark
-          statusEl.title = 'cpulimit is installed';
-          statusEl.classList.add('available');
-          statusEl.classList.remove('unavailable');
-          if (percentInput) percentInput.disabled = false;
-        } else {
-          statusEl.textContent = '\u2717';  // X mark
-          statusEl.title = 'cpulimit not installed (install with: apt install cpulimit)';
-          statusEl.classList.add('unavailable');
-          statusEl.classList.remove('available');
-          // Don't disable input, still allow setting the value for when it gets installed
-        }
-      }
-    } catch (err) {
-      statusEl.textContent = '?';
-      statusEl.title = 'Could not check cpulimit availability';
-    }
-  }
-
   applyHeaderVisibilitySettings() {
     const settings = this.loadAppSettingsFromStorage();
     // Default all to true (enabled) if not set

src/web/public/index.html

@@ -782,29 +782,21 @@
               </label>
               <span class="form-hint">Auto-enable for new sessions (otherwise auto-enables on Ralph pattern detection)</span>
             </div>
-            <!-- CPU Limiting Section -->
-            <div class="form-section-header">CPU Limiting</div>
+            <!-- Nice Priority Section -->
+            <div class="form-section-header">Nice Priority</div>
             <div class="form-row form-row-switch">
-              <label>Enable CPU Limiting</label>
+              <label>Enable Nice Priority Reduction</label>
               <label class="switch">
-                <input type="checkbox" id="appSettingsCpuLimitEnabled">
+                <input type="checkbox" id="appSettingsNiceEnabled">
                 <span class="slider"></span>
               </label>
-              <span class="form-hint">Limit CPU usage for Claude sessions (reduces system impact, only affects new sessions)</span>
+              <span class="form-hint">Lower priority of Claude sessions (reduces system impact, only affects new sessions)</span>
             </div>
-            <div class="form-row" id="cpuLimitNiceRow">
+            <div class="form-row" id="niceValueRow">
               <label>Nice Value</label>
-              <input type="number" id="appSettingsCpuNiceValue" min="-20" max="19" value="10" style="width: 80px;">
+              <input type="number" id="appSettingsNiceValue" min="-20" max="19" value="10" style="width: 80px;">
               <span class="form-hint">Process priority (-20 to 19, higher = lower priority, default: 10)</span>
             </div>
-            <div class="form-row" id="cpuLimitPercentRow">
-              <label>CPU Limit %</label>
-              <div class="settings-item-actions">
-                <input type="number" id="appSettingsCpuLimitPercent" min="1" max="100" value="80" style="width: 80px;">
-                <span class="cpu-limit-status" id="cpuLimitStatus" title="cpulimit availability status"></span>
-              </div>
-              <span class="form-hint">Hard CPU limit (requires cpulimit installed, default: 80%)</span>
-            </div>
           </div>
           <!-- Paths Tab -->
           <div class="modal-tab-content hidden" id="settings-paths">