docs: add comprehensive Broadcasting guide

Create in-depth, conversational documentation for NumPy-style broadcasting:

- Opens with motivation: the problem broadcasting solves (avoiding loops)
- Explains the core idea before diving into rules
- The Three Rules with visual alignment examples
- Multiple worked examples:
  - Scalar + Array
  - Row + Column (outer product pattern)
  - Matrix + Row vector (centering data)
  - Matrix + Column vector
  - Higher dimensions (batched operations)
- NumSharp broadcasting functions:
  - np.broadcast_to() with compatibility rules
  - np.broadcast_arrays() for explicit broadcasting
  - Implicit broadcasting in operations
- Why views matter (memory efficiency, read-only behavior)
- Common pitfalls:
  - Shape mismatch errors and how to debug
  - Row vs column confusion
  - Accidentally broadcasting
  - Memory explosion risks
- Performance considerations
- How NumSharp implements it (stride manipulation)
- Quick reference tables for compatible/incompatible shapes

Written in conversational tone that explains "why" not just "what".

Author: Nucs

docs/website-src/docs/broadcasting.md

@@ -1,5 +1,7 @@
 - name: Introduction
   href: intro.md
+- name: Broadcasting
+  href: broadcasting.md
 - name: NumPy Compliance & Compatibility
   href: compliance.md
 - name: Array API Standard

docs/website-src/docs/toc.yml

@@ -15,6 +15,9 @@
                 <li>
                     <a href="intro.html" name="" title="Introduction">Introduction</a>
                 </li>
+                <li>
+                    <a href="broadcasting.html" name="" title="Broadcasting">Broadcasting</a>
+                </li>
                 <li>
                     <a href="compliance.html" name="" title="NumPy Compliance &amp; Compatibility">NumPy Compliance &amp; Compatibility</a>
                 </li>

docs/website/docs/broadcasting.html

@@ -1,2 +1,2 @@
 
-{"items":[{"name":"Introduction","href":"intro.html","topicHref":"intro.html"},{"name":"NumPy Compliance & Compatibility","href":"compliance.html","topicHref":"compliance.html"},{"name":"Array API Standard","href":"array-api-standard.html","topicHref":"array-api-standard.html"},{"name":"Extending Libraries","href":"extensions/index.html","topicHref":"extensions/index.html","items":[{"name":"NumSharp.Bitmap","href":"extensions/bitmap.html","topicHref":"extensions/bitmap.html"}],"expanded":false}]}
+{"items":[{"name":"Introduction","href":"intro.html","topicHref":"intro.html"},{"name":"Broadcasting","href":"broadcasting.html","topicHref":"broadcasting.html"},{"name":"NumPy Compliance & Compatibility","href":"compliance.html","topicHref":"compliance.html"},{"name":"Array API Standard","href":"array-api-standard.html","topicHref":"array-api-standard.html"},{"name":"Extending Libraries","href":"extensions/index.html","topicHref":"extensions/index.html","items":[{"name":"NumSharp.Bitmap","href":"extensions/bitmap.html","topicHref":"extensions/bitmap.html"}],"expanded":false}]}

docs/website/docs/toc.html

@@ -1322,6 +1322,16 @@
       },
       "version": ""
     },
+    {
+      "type": "Conceptual",
+      "source_relative_path": "docs/broadcasting.md",
+      "output": {
+        ".html": {
+          "relative_path": "docs/broadcasting.html"
+        }
+      },
+      "version": ""
+    },
     {
       "type": "Conceptual",
       "source_relative_path": "docs/compliance.md",