feat: add three viewing modes for app specification (#566)

* feat: add three viewing modes for app specification

Introduces View, Edit, and Source modes for the spec page:

- View: Clean read-only display with cards, badges, and accordions
- Edit: Structured form-based editor for all spec fields
- Source: Raw XML editor for advanced users

Also adds @automaker/spec-parser shared package for XML parsing
between server and client.

* fix: address PR review feedback

- Replace array index keys with stable UUIDs in array-field-editor,
  features-section, and roadmap-section components
- Replace regex-based XML parsing with fast-xml-parser for robustness
- Simplify renderContent logic in spec-view by removing dead code paths

* fix: convert git+ssh URLs to https in package-lock.json

* fix: address PR review feedback for spec visualiser

- Remove unused RefreshCw import from spec-view.tsx
- Add explicit parsedSpec check in renderContent for robustness
- Hide save button in view mode since it's read-only
- Remove GripVertical drag handles since drag-and-drop is not implemented
- Rename Map imports to MapIcon to avoid shadowing global Map
- Escape tagName in xml-utils.ts RegExp functions for safety
- Add aria-label attributes for accessibility on mode tabs

* fix: address additional PR review feedback

- Fix Textarea controlled/uncontrolled warning with default value
- Preserve IDs in useEffect sync to avoid unnecessary remounts
- Consolidate lucide-react imports
- Add JSDoc note about tag attributes limitation in xml-utils.ts
- Remove redundant disabled prop from SpecModeTabs

libs/spec-parser/src/spec-to-xml.ts

@@ -0,0 +1,88 @@
+/**
+ * SpecOutput to XML converter.
+ * Converts a structured SpecOutput object back to XML format.
+ */
+
+import type { SpecOutput } from '@automaker/types';
+import { escapeXml } from './xml-utils.js';
+
+/**
+ * Convert structured spec output to XML format.
+ *
+ * @param spec - The SpecOutput object to convert
+ * @returns XML string formatted for app_spec.txt
+ */
+export function specToXml(spec: SpecOutput): string {
+  const indent = '  ';
+
+  let xml = `<?xml version="1.0" encoding="UTF-8"?>
+<project_specification>
+${indent}<project_name>${escapeXml(spec.project_name)}</project_name>
+
+${indent}<overview>
+${indent}${indent}${escapeXml(spec.overview)}
+${indent}</overview>
+
+${indent}<technology_stack>
+${spec.technology_stack.map((t) => `${indent}${indent}<technology>${escapeXml(t)}</technology>`).join('\n')}
+${indent}</technology_stack>
+
+${indent}<core_capabilities>
+${spec.core_capabilities.map((c) => `${indent}${indent}<capability>${escapeXml(c)}</capability>`).join('\n')}
+${indent}</core_capabilities>
+
+${indent}<implemented_features>
+${spec.implemented_features
+  .map(
+    (f) => `${indent}${indent}<feature>
+${indent}${indent}${indent}<name>${escapeXml(f.name)}</name>
+${indent}${indent}${indent}<description>${escapeXml(f.description)}</description>${
+      f.file_locations && f.file_locations.length > 0
+        ? `\n${indent}${indent}${indent}<file_locations>
+${f.file_locations.map((loc) => `${indent}${indent}${indent}${indent}<location>${escapeXml(loc)}</location>`).join('\n')}
+${indent}${indent}${indent}</file_locations>`
+        : ''
+    }
+${indent}${indent}</feature>`
+  )
+  .join('\n')}
+${indent}</implemented_features>`;
+
+  // Optional sections
+  if (spec.additional_requirements && spec.additional_requirements.length > 0) {
+    xml += `
+
+${indent}<additional_requirements>
+${spec.additional_requirements.map((r) => `${indent}${indent}<requirement>${escapeXml(r)}</requirement>`).join('\n')}
+${indent}</additional_requirements>`;
+  }
+
+  if (spec.development_guidelines && spec.development_guidelines.length > 0) {
+    xml += `
+
+${indent}<development_guidelines>
+${spec.development_guidelines.map((g) => `${indent}${indent}<guideline>${escapeXml(g)}</guideline>`).join('\n')}
+${indent}</development_guidelines>`;
+  }
+
+  if (spec.implementation_roadmap && spec.implementation_roadmap.length > 0) {
+    xml += `
+
+${indent}<implementation_roadmap>
+${spec.implementation_roadmap
+  .map(
+    (r) => `${indent}${indent}<phase>
+${indent}${indent}${indent}<name>${escapeXml(r.phase)}</name>
+${indent}${indent}${indent}<status>${escapeXml(r.status)}</status>
+${indent}${indent}${indent}<description>${escapeXml(r.description)}</description>
+${indent}${indent}</phase>`
+  )
+  .join('\n')}
+${indent}</implementation_roadmap>`;
+  }
+
+  xml += `
+</project_specification>`;
+
+  return xml;
+}