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/index.ts

@@ -0,0 +1,26 @@
+/**
+ * @automaker/spec-parser
+ *
+ * XML spec parser for AutoMaker - parses and generates app_spec.txt XML.
+ * This package provides utilities for:
+ * - Parsing XML spec content into SpecOutput objects
+ * - Converting SpecOutput objects back to XML
+ * - Validating spec data
+ */
+
+// Re-export types from @automaker/types for convenience
+export type { SpecOutput } from '@automaker/types';
+
+// XML utilities
+export { escapeXml, unescapeXml, extractXmlSection, extractXmlElements } from './xml-utils.js';
+
+// XML to Spec parsing
+export { xmlToSpec } from './xml-to-spec.js';
+export type { ParseResult } from './xml-to-spec.js';
+
+// Spec to XML conversion
+export { specToXml } from './spec-to-xml.js';
+
+// Validation
+export { validateSpec, isValidSpecXml } from './validate.js';
+export type { ValidationResult } from './validate.js';