refactor: complete three-layer serial refactoring (knowledge→schema→renderer)

Step 1 — Knowledge base: perfect all reference/*.md with type, range, default, unit
- text.md: add DataOrPathProps, path/data, bullet deprecated params
- chart.md: add deprecated section, fix 19 params with missing elements
- slide.md: add bkgd→background deprecated mapping
- output.md: add masterSlide, presLayout

Step 2 — Schema: align schema/presentation.schema.json with KB
- Add catAxisItem and valAxisItem definitions with full sub-property constraints
- Fix 7 enum constraints (barDir, displayBlanksAs, bar3DShape, etc.)
- Add 4 missing fields (verbose, autoPageCharWeight, autoPageLineWeight, notes,
  masterSlide, presLayout)

Step 3 — Translation engine: transform renderers from passthrough to validation
- index.js: add normalizePosition, normalizeColor, validateEnum shared utilities
- All renderers: position validation, color hex normalization, enum validation
- Image: graceful failure handling (catch load errors, warn, continue)
- Chart: chartType enum validation, data parity check
- Table: colspan/rowspan integer validation, border array check
- Full verification: basic.json and full.json generate valid PPTX

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

renderer/image-renderer.js

@@ -1,5 +1,28 @@
+var { normalizePosition, normalizeColorInOptions, validateEnum } = require('./index');
+
 function renderImage(slide, imageData) {
-  slide.addImage(imageData.options);
+  var opts = {};
+  if (imageData.options) {
+    for (var k in imageData.options) {
+      if (imageData.options.hasOwnProperty(k)) opts[k] = imageData.options[k];
+    }
+  }
+
+  normalizePosition(opts);
+
+  if (opts.sizing && typeof opts.sizing === 'object') {
+    validateEnum(opts.sizing.type, ['contain', 'cover', 'crop'], 'sizing.type');
+  }
+  if (opts.shadow && typeof opts.shadow === 'object') {
+    normalizeColorInOptions(opts.shadow, 'color');
+    validateEnum(opts.shadow.type, ['outer', 'inner', 'none'], 'shadow.type');
+  }
+
+  try {
+    slide.addImage(opts);
+  } catch (e) {
+    console.warn('Failed to load image: ' + (opts.path || 'unknown'));
+  }
 }
 
 module.exports = { renderImage };