feat: Script Generator Phase 1+2 — backend, engine, API, frontend, template editor, parameter detector

Complete Script Generator feature including:

Backend:
- ScriptCategory, ScriptTemplate, ScriptGeneration models
- ScriptTemplateEngine with substitution, filters, sanitization
- CRUD + share API endpoints with permission checks
- Integration tests for permissions and sharing
- Migration 057 with AD User Management seed templates

Frontend — Script Library:
- Browse templates with category tabs and search
- Configure pane with parameter form and script generation
- Script preview with live substitution and copy/download
- scriptGeneratorStore Zustand store

Frontend — Template Editor:
- Full CRUD form with metadata, script body (Monaco Editor), parameters
- ParameterSchemaBuilder with visual builder + JSON toggle
- ScriptManagePage with routing and nav link

Frontend — Parameter Detector:
- Client-side PowerShell parameter detection engine
- Detects script-level param() blocks and variable assignments
- Type inference from PS type annotations and value patterns
- ParameterDetectorStepper one-by-one review UI with accept/skip

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/pages/ScriptLibraryPage.tsx

@@ -0,0 +1,98 @@
+import { useState, useEffect } from 'react'
+import { Link } from 'react-router-dom'
+import { Terminal, Settings } from 'lucide-react'
+import { useScriptGeneratorStore } from '@/store/scriptGeneratorStore'
+import { usePermissions } from '@/hooks/usePermissions'
+import { ScriptFilterBar } from '@/components/scripts/ScriptFilterBar'
+import { ScriptTemplateList } from '@/components/scripts/ScriptTemplateList'
+import { ScriptConfigurePane } from '@/components/scripts/ScriptConfigurePane'
+import { ScriptPreview } from '@/components/scripts/ScriptPreview'
+
+export default function ScriptLibraryPage() {
+  const [paneMode, setPaneMode] = useState<'browse' | 'configure'>('browse')
+  // inputValue owned here so it survives Configure ↔ Browse transitions
+  const [inputValue, setInputValue] = useState('')
+
+  const loadCategories = useScriptGeneratorStore(s => s.loadCategories)
+  const loadTemplates = useScriptGeneratorStore(s => s.loadTemplates)
+  const setSearch = useScriptGeneratorStore(s => s.setSearch)
+  const selectTemplate = useScriptGeneratorStore(s => s.selectTemplate)
+  const clearOutput = useScriptGeneratorStore(s => s.clearOutput)
+  const selectedTemplate = useScriptGeneratorStore(s => s.selectedTemplate)
+
+  const { isEngineer } = usePermissions()
+  const canGenerate = isEngineer
+
+  useEffect(() => {
+    loadCategories().then(() => loadTemplates())
+  }, [loadCategories, loadTemplates])
+
+  const onClearSearch = () => {
+    setInputValue('')
+    setSearch('')
+  }
+
+  const onConfigure = (id: string) => {
+    selectTemplate(id)
+    setPaneMode('configure')
+  }
+
+  const onBack = () => {
+    clearOutput()
+    setPaneMode('browse')
+  }
+
+  return (
+    <div className="flex flex-col gap-4 p-6 h-full">
+      {/* Page header */}
+      <div>
+        <h1 className="text-2xl font-heading font-bold text-foreground">Script Library</h1>
+        <p className="text-sm text-muted-foreground mt-1">
+          Browse PowerShell templates, fill in parameters, and generate ready-to-run scripts.
+        </p>
+        {isEngineer && (
+          <Link
+            to="/scripts/manage"
+            className="inline-flex items-center gap-1.5 text-xs text-primary bg-primary/10 hover:bg-primary/15 px-2.5 py-1 rounded-full transition-colors mt-2 group"
+          >
+            <Settings size={12} className="group-hover:rotate-90 transition-transform duration-300" />
+            Manage Templates
+          </Link>
+        )}
+      </div>
+
+      {/* Two-column layout */}
+      <div className="grid grid-cols-[320px_1fr] gap-4 flex-1 min-h-0">
+        {/* Left pane — Browse or Configure mode */}
+        {paneMode === 'browse' ? (
+          <div className="glass-card-static flex flex-col overflow-hidden">
+            <div className="p-2 pb-0">
+              <ScriptFilterBar inputValue={inputValue} setInputValue={setInputValue} />
+            </div>
+            <div className="flex-1 overflow-y-auto">
+              <ScriptTemplateList
+                inputValue={inputValue}
+                onClearSearch={onClearSearch}
+                onConfigure={onConfigure}
+              />
+            </div>
+          </div>
+        ) : (
+          <ScriptConfigurePane canGenerate={canGenerate} onBack={onBack} />
+        )}
+
+        {/* Right pane — read-only ScriptPreview */}
+        {selectedTemplate === null ? (
+          <div className="glass-card-static h-full flex flex-col items-center justify-center gap-3 text-center p-8">
+            <Terminal size={40} className="text-muted-foreground/40" />
+            <p className="text-sm text-muted-foreground">Select a template to get started</p>
+          </div>
+        ) : (
+          <div className="glass-card-static h-full overflow-y-auto p-4">
+            <ScriptPreview />
+          </div>
+        )}
+      </div>
+    </div>
+  )
+}