docs: improve README conversion — fix Quick Start, reorder sections

- Remove redundant include DSL (Assertions already includes it)
- Add git add/commit step to Quick Start (prevents CI failure)
- Lead "What You Get" with failure message, not file table
- Move standalone compare API into "What You Get" (strong hook)
- Rename "Configuration" → "Tuning Flaky Tests" (after Next Steps)
- Move Troubleshooting after Next Steps (not before)
- Simplify first-run explanation (no conflicting RECORD_SCREENSHOTS)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: pftg

README.md

@@ -19,47 +19,59 @@ require 'capybara_screenshot_diff/minitest'
 ```
 
 ```ruby
-# test/application_system_test_case.rb (or test/system/homepage_test.rb)
+# test/application_system_test_case.rb
 class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
-  include CapybaraScreenshotDiff::DSL
   include CapybaraScreenshotDiff::Minitest::Assertions
 end
+```
 
+```ruby
+# test/system/homepage_test.rb
 class HomepageTest < ApplicationSystemTestCase
   test "homepage" do
     visit "/"
-    screenshot "homepage"  # First run: saves baseline. Next runs: compares.
+    screenshot "homepage"
   end
 end
 ```
 
-That's it. No configuration needed. Screenshots are saved to `doc/screenshots/` and compared on each test run.
+```bash
+bundle exec rake test                    # First run always passes — saves baselines
+bundle exec rake test                    # Second run compares against baselines
+git add doc/screenshots/
+git commit -m "chore: add screenshot baselines"
+```
+
+That's it. The first run saves baseline screenshots (always passes). Subsequent runs compare against them — if the UI changed, the test fails. Commit baselines to git so CI catches regressions.
 
-> **First run:** saves baseline screenshots (tests pass).
-> **Second run:** compares against baselines. If anything changed, the test fails with a diff.
-> **Commit baselines to git** so CI catches regressions too.
+> **CI note:** In CI, `fail_if_new` is `true` by default — new screenshots without a committed baseline will fail. Always commit your baselines before pushing.
 
 For RSpec, Cucumber, or non-Rails setup, see [Framework Setup](docs/framework-setup.md).
 
 ## What You Get
 
-When a screenshot differs, you get:
+When a screenshot differs, the test fails with a clear message:
 
-| File | Description |
-|------|-------------|
-| `homepage.png` | Committed baseline (in version control) |
-| `homepage.base.png` | Runtime copy of baseline (for comparison) |
-| `homepage.diff.png` | Visual diff with changes highlighted in red |
-| `homepage.heatmap.diff.png` | Heatmap of pixel differences |
-
-The failure message tells you exactly what changed:
 ```text
 Screenshot does not match for 'homepage':
 ({"area_size":1250,"region":[0,19,199,83],"max_color_distance":42.5})
 ```
 
+And generates diff files for inspection:
+
+| File | Description |
+|------|-------------|
+| `homepage.png` | Committed baseline |
+| `homepage.diff.png` | Visual diff with changes highlighted in red |
+| `homepage.heatmap.diff.png` | Heatmap of pixel differences |
+
 Enable the [HTML report](docs/reporters.md) for an interactive dashboard with side-by-side comparison, zoom, and annotation toggle.
 
+**Compare any two images** without a browser — PDFs, generated images, CI artifacts:
+```ruby
+Capybara::Screenshot::Diff.compare("baseline.png", "current.png")
+```
+
 ## Installation
 
 ```ruby
@@ -74,11 +86,18 @@ Then run `bundle install`.
 
 **Requirements:** Ruby 3.2+, Rails 7.1+. For the `:vips` driver: [libvips 8.9+](https://libvips.github.io/libvips/install.html).
 
-## Configuration
+## Next Steps
+
+- **Crop to element:** `screenshot "form", crop: "#main-form"`
+- **Ignore regions:** `screenshot "dashboard", skip_area: [".timestamp"]`
+- **Run in CI:** See [GitHub Actions setup](docs/ci-integration.md)
+- **HTML report:** `require 'capybara_screenshot_diff/reporters/html'` — [details](docs/reporters.md)
 
-**Works out of the box.** `blur_active_element`, `hide_caret`, and `fail_if_new` (in CI) are enabled by default.
+## Tuning Flaky Tests
 
-When tests are flaky, add tolerance:
+**Defaults work for most Rails apps.** `blur_active_element`, `hide_caret`, and `fail_if_new` (in CI) are enabled automatically.
+
+If you see inconsistent results, add tolerance:
 
 ```ruby
 Capybara::Screenshot::Diff.configure do |screenshot, diff|
@@ -97,7 +116,7 @@ See [Configuration Reference](docs/configuration.md) for all options.
 
 ## Troubleshooting
 
-**"No existing screenshot found"** — First run saves baselines. Record them: `RECORD_SCREENSHOTS=1 bundle exec rake test`. In CI, commit baselines first.
+**"No existing screenshot found"** — First run saves baselines. Run `bundle exec rake test` twice, then commit `doc/screenshots/`.
 
 **Screenshots differ between CI and local** — Use `tolerance: 0.001` or `perceptual_threshold: 2.0`. Set `window_size` for consistent dimensions.
 
@@ -107,14 +126,6 @@ See [Configuration Reference](docs/configuration.md) for all options.
 
 **Debug mode** — `DEBUG=1 bundle exec rake test` keeps `.diff.png` files for inspection.
 
-## Next Steps
-
-- **Crop to element:** `screenshot "form", crop: "#main-form"`
-- **Ignore regions:** `screenshot "dashboard", skip_area: [".clock"]`
-- **Run in CI:** See [GitHub Actions setup](docs/ci-integration.md)
-- **HTML report:** `require 'capybara_screenshot_diff/reporters/html'` — [details](docs/reporters.md)
-- **Compare any images:** `Capybara::Screenshot::Diff.compare("a.png", "b.png")` — no browser needed
-
 ## Advanced Topics
 
 - [Framework Setup](docs/framework-setup.md) — Minitest, RSpec, Cucumber