Allow reordering terminal tabs via drag and drop

[vogella]

Dragging a terminal tab within the same Terminals view now reorders it to the drop position, the same way editor and view tabs can be rearranged.
Previously a drop inside the originating view was rejected, so tabs could only be moved to a different Terminals view.

The reorder relies on the new CTabFolder.moveItem(int, int) API (SWT 3.135, eclipse-platform/eclipse.platform.swt#3350), which keeps the live terminal control attached instead of recreating it.
The existing cross-view move is left untouched because transferring a terminal to a different view still requires re-parenting.

Draft because it depends on SWT 3.135, which is not yet in the platform target platform, so CI cannot build it until that lands.

Fixes #2679

[github-actions]

Test Results

    54 files  ± 0      54 suites  ±0   36m 47s ⏱️ + 1m 10s
 4 673 tests + 6   4 646 ✅ +1   22 💤 ±0  0 ❌ ±0   5 🔥 + 5 
11 913 runs  +18  11 745 ✅ +3  153 💤 ±0  0 ❌ ±0  15 🔥 +15 

For more details on these errors, see this check.

Results for commit 75a1ea4. ± Comparison against base commit 859044c.

♻️ This comment has been updated with latest results.

[vogella]

Needs the change in SWT, which should be available tomorrow, after that this can be tested.

[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:

terminal/features/org.eclipse.terminal.feature/feature.xml

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 ed891f2476a356fc9e091c8568fc8d01afde2021 Mon Sep 17 00:00:00 2001
From: Eclipse Platform Bot <platform-bot@eclipse.org>
Date: Wed, 3 Jun 2026 08:17:43 +0000
Subject: [PATCH] Version bump(s) for 4.41 stream


diff --git a/terminal/features/org.eclipse.terminal.feature/feature.xml b/terminal/features/org.eclipse.terminal.feature/feature.xml
index 94b37131c2..044c0b1ba2 100644
--- a/terminal/features/org.eclipse.terminal.feature/feature.xml
+++ b/terminal/features/org.eclipse.terminal.feature/feature.xml
@@ -2,7 +2,7 @@
 <feature
       id="org.eclipse.terminal.feature"
       label="%featureName"
-      version="1.0.300.qualifier"
+      version="1.0.400.qualifier"
       provider-name="%providerName"
       license-feature="org.eclipse.license"
       license-feature-version="0.0.0">
-- 
2.54.0

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