doc: add missing docs here and there

Author: Platonn

projects/storefrontstyles/scss/components/content/media/_media.scss

@@ -3,7 +3,8 @@
   display: block;
 
   img {
-    // SPIKE NEW - necessary for responsive images, but it's a breaking change. needs feature toggle.
+    // SPIKE NEW - necessary for responsive images
+    // SPIKE TODO: it's a breaking change so needs extensive testing and a feature toggle.
     width: 100%;
     height: auto;
     // SPIKE END

projects/storefrontstyles/scss/theme/sparta/_fonts.scss

@@ -1,4 +1,4 @@
-// SPIKE TODO UNCOMMENT AND FIX/OPTIMIZE - now removed temporarily to improve LCP
+// SPIKE TODO UNCOMMENT AND FIX/OPTIMIZE OTHER WAY - now removed to improve LCP
 // @import '@fontsource/open-sans/300.css';
 // @import '@fontsource/open-sans/400.css';
 // @import '@fontsource/open-sans/600.css';

test-app/src/custom/CUSTOMIZATIONS-OUTSIDE-THIS-FOLDER.md

@@ -2,5 +2,11 @@ All customizations of the `test-app` should be kept in the folder `src/app/custo
 
 Any exceptional customizations made outside of the folder `src/app/custom` should be documented in this file:
 
-- `src/app/app.module.ts`: include all our `customProviders` from this folder `src/app/custom`
-- `src/styles.scss`: include all our custom styles from this folder `src/app/custom`
+### `src/app/app.module.ts`
+Provide all our `customProviders` from this folder `src/app/custom`
+
+### `src/styles.scss`
+Import all our custom styles from this folder `src/app/custom`
+
+### `angular.json`
+Generate source maps also for _vendor_ libs (in this case `@spartacus` libs are vendor coming from `test-app/node_modules`) - both in dev and prod mode build.

test-app/src/custom/workaround-extract-banner-dimensions-from-url.ts

@@ -95,7 +95,6 @@ export class CustomOccCmsPageNormalizer extends OccCmsPageNormalizer {
   } {
     // Banner images in our sample data happen to follow the pattern `somename-WIDTHxHEIGHT-somename...`
     // so we can leverage it to extract the dimensions
-    // (yes it's a workaround! ideally dimensions should be defined in CMS!)
     const pattern = /\/medias\/[^-]+-(\d+)x(\d+)-[^-]+/;
     const match = url.match(pattern);
     if (match) {

test-app/src/custom/workaround-mark-certain-banners-as-lcp.ts

@@ -2,6 +2,13 @@ import { Injectable, Provider } from '@angular/core';
 import { CmsBannerComponent } from '@spartacus/core';
 import { BannerComponentService } from '@spartacus/storefront';
 
+/**
+ * Marks certain banners as LCP (Largest Contentful Paint), making them
+ * fetched with high priority.
+ *
+ * (yes it's a workaround! ideally such information should not be hardcoded in Spartacus
+ * by "component name" but rather defined in CMS!)
+ */
 @Injectable({ providedIn: 'root' })
 export class CustomBannerComponentService extends BannerComponentService {
   override getImageFetchPriority(