Fix documentation H1 headings for improved search indexing

Add missing H1 headings and improve H1 quality across 10 documentation
files to enable proper Algolia search indexing and improve accessibility.

Critical fixes (missing H1):
- configuration.md: Add "React on Rails Configuration Options"
- react-on-rails-pro.md: Change H2 to H1
- rails-engine-integration.md: Add "Integrating React on Rails with Rails Engines"
- troubleshooting-when-using-webpacker.md: Add H1 and fix structure
- troubleshooting-when-using-shakapacker.md: Add H1 and fix heading hierarchy
- credits.md: Add "React on Rails Credits and Authors"

Quality improvements (better searchability):
- images.md: "Images" → "Configuring Images and Assets with Webpack"
- foreman-issues.md: "Foreman Issues" → "Troubleshooting Foreman with React on Rails"
- updating-dependencies.md: "Updating Dependencies" → "Updating Ruby and JavaScript Dependencies"
- api-reference/README.md: "API Reference" → "React on Rails API Reference Guide"

Why: Algolia indexes H1 as primary title. Files without H1 show as
"Untitled" in search results. Generic H1s reduce searchability.

Reference: docs/planning/docs-improvement/h1-headings-audit-report.md
(local file, not tracked)

Author: ihabadham

docs/advanced-topics/rails-engine-integration.md

@@ -1,3 +1,5 @@
+# Integrating React on Rails with Rails Engines
+
 ## In your engine
 
 - At the top of `config/initializers/react_on_rails.rb`

docs/api-reference/README.md

@@ -1,4 +1,4 @@
-# API Reference
+# React on Rails API Reference Guide
 
 Complete API documentation for React on Rails.
 

docs/api-reference/configuration.md

@@ -1,3 +1,5 @@
+# React on Rails Configuration Options
+
 Here is the full set of config options. This file is `/config/initializers/react_on_rails.rb`
 
 First, you should have a `/config/shakapacker.yml` setup.

docs/building-features/foreman-issues.md

@@ -1,4 +1,4 @@
-# Foreman Issues
+# Troubleshooting Foreman with React on Rails
 
 ## It is not recommended to include foreman into Gemfile
 

docs/building-features/images.md

@@ -1,4 +1,4 @@
-# Images
+# Configuring Images and Assets with Webpack
 
 1. leading slash necessary on the
    a. Option name for the file-loader and url-loader (todo reference)

docs/deployment/troubleshooting-when-using-shakapacker.md

@@ -1,13 +1,15 @@
-# Client rendering crashes when configuring `optimization.runtimeChunk` to `multiple`
+# Troubleshooting Shakapacker Configuration Issues
 
-## Context
+## Client rendering crashes when configuring `optimization.runtimeChunk` to `multiple`
+
+### Context
 
 1. Ruby version: 3.1
 2. Rails version: 7.0.6
 3. Shakapacker version: 6.6.0
 4. React on Rails version: 13.3.5
 
-## The failure
+### The failure
 
 Configuring Webpack to embed the runtime in each chunk and calling `react_component` twice in a Rails view/partial causes the client render to crash with the following error:
 
@@ -27,31 +29,31 @@ VM4859 clientStartup.js:132 Uncaught Error: ReactOnRails encountered an error wh
     at HTMLDocument.onReadyStateChange (VM4859 clientStartup.js:238:13)
 ```
 
-## Configs
+### Configs
 
-### Webpack configuration
+#### Webpack configuration
 
 ```js
 optimization: {
   runtimeChunk: 'multiple'
 },
 ```
 
-### Rails view
+#### Rails view
 
 ```haml
 = react_component("XXX", props: @props)
 = yield
 = react_component("YYY", props: @props)
 ```
 
-## The problem
+### The problem
 
 Configuring Webpack to embed the runtime in each chunk and calling `react_component` twice in a Rails view/partial causes the client render to crash.
 
 Read more at https://github.com/shakacode/react_on_rails/issues/1558.
 
-## Solution
+### Solution
 
 To overcome this issue, we could use [shakapacker](https://github.com/shakacode/shakapacker)'s default optimization configuration (pseudo-code):
 

docs/deployment/troubleshooting-when-using-webpacker.md

@@ -1,3 +1,5 @@
+# Troubleshooting Webpacker Manifest Errors
+
 ## Context
 
 Rails: 5.0.2

docs/misc/credits.md

@@ -1,3 +1,5 @@
+# React on Rails Credits and Authors
+
 ## Authors
 
 [The Shaka Code team!](http://www.shakacode.com/about/)

docs/misc/updating-dependencies.md

@@ -1,4 +1,4 @@
-# Updating Dependencies
+# Updating Ruby and JavaScript Dependencies
 
 If you frequently update dependencies in small batches, you will avoid large and painful updates later. Then again, if you don't have good test coverage, it's hazardous to update dependencies at any time.
 

docs/pro/react-on-rails-pro.md

@@ -1,4 +1,4 @@
-## React on Rails Pro
+# React on Rails Pro
 
 Support React on Rails development [by becoming a Github sponsor](https://github.com/sponsors/shakacode) and get these benefits: