CDN 2025 chapter (#4348)

* Fixed missing zstd compression type

* Added tls, early hints, image format, cdn usage and tls graphics.

* Added images, wrote first half of mark down.

* Updated markdown, added all major sections.

* Updated intro and cdn performance section.

* Updated conclusion.

* Added cdn security header section, updated conclusion.

* grammatical fixes

* Additional grammatical, spelling, and content changes

* Enable chapter

* Technical edits

* Edits

* Update cdn.md based on review

Updates provided by amoen

* Final edits

---------

Co-authored-by: Joe Viggiano <17817811+joeviggiano@users.noreply.github.com>
Co-authored-by: Barry Pollard <barrypollard@google.com>

Author: 3 people

sql/2025/cdn/distribution_of_compression_types_by_cdn.sql

@@ -15,6 +15,7 @@ FROM (
     CASE
       WHEN a.value = 'gzip' THEN 'Gzip'
       WHEN a.value = 'br' THEN 'Brotli'
+      WHEN a.value = 'zstd' THEN 'Zstandard'
       WHEN a.value = '' THEN 'no text compression'
       ELSE 'other'
     END AS compression_type

sql/2025/cdn/distribution_of_compression_types_cdn_vs_origin.sql

@@ -15,6 +15,7 @@ FROM (
     CASE
       WHEN a.value = 'gzip' THEN 'Gzip'
       WHEN a.value = 'br' THEN 'Brotli'
+      WHEN a.value = 'zstd' THEN 'Zstandard'
       WHEN a.value = '' THEN 'no text compression'
       ELSE 'other'
     END AS compression_type

src/config/2025.json

@@ -126,8 +126,7 @@
           "part": "IV",
           "chapter_number": "15",
           "title": "CDN",
-          "slug": "cdn",
-          "todo": true
+          "slug": "cdn"
         },
         {
           "part": "IV",

src/config/contributors.json

@@ -311,6 +311,10 @@
       "2024": [
         "analysts",
         "authors"
+      ],
+      "2025": [
+        "analysts",
+        "authors"
       ]
     }
   },
@@ -1061,6 +1065,10 @@
       "2024": [
         "reviewers",
         "editors"
+      ],
+      "2025": [
+        "reviewers",
+        "editors"
       ]
     }
   },
@@ -2494,6 +2502,10 @@
       ],
       "2024": [
         "authors"
+      ],
+      "2025": [
+        "analysts",
+        "authors"
       ]
     }
   },
@@ -3589,6 +3601,18 @@
       ]
     }
   },
+  "nick-mccord": {
+    "avatar_url": "102171522",
+    "github": "nick-mccord",
+    "linkedin": "nicholasmccord",
+    "name": "Nick McCord",
+    "teams": {
+      "2025": [
+        "analysts",
+        "authors"
+      ]
+    }
+  },
   "phacks": {
     "avatar_url": "2587348",
     "github": "phacks",