Remove unused CSS serializer classes and dead color converter config

[vogella]

The CSSSerializer / CSSSerializerConfiguration / CSSHTMLSerializerConfiguration trio in org.eclipse.e4.ui.css.core.serializers and CSSSWTSerializerConfiguration in org.eclipse.e4.ui.css.swt.serializers have no callers in the production tree or in any built test bundle. Their only references are in tests/.../tkuiTestsToRefactor, the quarantined refactor backlog that is not part of any test build. Drop the four classes and the matching x-friends/x-internal exports for the two serializers packages from the bundle manifests.

Drop ICSSValueConverterColorConfig and CSSValueConverterConfigColorImpl in the same pass: the COLOR_HEXA_FORMAT_CONFIG / COLOR_NAME_FORMAT_CONFIG / COLOR_RGB_FORMAT_CONFIG instances those classes provide are never constructed by any caller, so the corresponding instanceof branch in CSS2ColorHelper.getColorStringValue is unreachable and the helper always returns the hex form. Simplify the helper to drop its ICSSValueConverterConfig parameter and update the two SWT color converters that called it.

All bundles internal (x-friends/x-internal), no API surface affected.

[eclipse-platform-bot]

This pull request changes some projects for the first time in this development cycle.
Therefore the following files need a version increment:

bundles/org.eclipse.e4.ui.css.core/META-INF/MANIFEST.MF

An additional commit containing all the necessary changes was pushed to the top of this PR's branch. To obtain these changes (for example if you want to push more changes) either fetch from your fork or apply the git patch.

Git patch

From 95143be51f2454810126fe80cd7eaffb9993677d Mon Sep 17 00:00:00 2001
From: Eclipse Platform Bot <platform-bot@eclipse.org>
Date: Thu, 7 May 2026 04:12:28 +0000
Subject: [PATCH] Version bump(s) for 4.40 stream


diff --git a/bundles/org.eclipse.e4.ui.css.core/META-INF/MANIFEST.MF b/bundles/org.eclipse.e4.ui.css.core/META-INF/MANIFEST.MF
index 77f1ae4362..a911add12a 100644
--- a/bundles/org.eclipse.e4.ui.css.core/META-INF/MANIFEST.MF
+++ b/bundles/org.eclipse.e4.ui.css.core/META-INF/MANIFEST.MF
@@ -4,7 +4,7 @@ Bundle-SymbolicName: org.eclipse.e4.ui.css.core;singleton:=true
 Bundle-Name: %pluginName
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
-Bundle-Version: 0.14.600.qualifier
+Bundle-Version: 0.14.700.qualifier
 Export-Package: org.eclipse.e4.ui.css.core;x-internal:=true,
  org.eclipse.e4.ui.css.core.css2;x-friends:="org.eclipse.e4.ui.css.swt.theme,org.eclipse.e4.ui.css.swt,org.eclipse.e4.ui.css.jface",
  org.eclipse.e4.ui.css.core.dom;x-friends:="org.eclipse.e4.ui.css.swt,org.eclipse.ui.views.properties.tabbed,org.eclipse.ui.forms",
-- 
2.53.0

Further information are available in Common Build Issues - Missing version increments.

[github-actions]

Test Results

   851 files   - 1     851 suites   - 1   50m 3s ⏱️ - 7m 24s
 7 954 tests ±0   7 711 ✅ ±0  243 💤 ±0  0 ❌ ±0 
20 361 runs   - 3  19 706 ✅  - 3  655 💤 ±0  0 ❌ ±0 

Results for commit 2d8091f. ± Comparison against base commit 7e65263.

[vogella]

A grep across eclipse.pde for any of those names or the two *.serializers package paths returns zero matches, and the PR description notes the affected packages are x-friends/x-internal with no API surface change. So this PR should not affect the eclipse.pde repo.