Host the manual's images in the repo under manual/images (#6861)

* Host the manual's images in the repo under manual/images

Replaces all learn.omacom.io/manual.omakub.org hotlinks with local webp
files capped at 1600px wide (~20MB total), so the manual is fully
self-contained. Theme and unlock previews are converted from the
canonical themes/*/preview.png files. A handful of illustration shots
are interim conversions of the current images, pending retakes.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Retake the illustration screenshots fresh at 3x scaling

Navigation, clipboard history, notices, tmux layouts, prompt, and About
reshot on a clean workspace at 3.13x (1920x1080 logical on 6K) across
ten themes: Tokyo Night, Catppuccin, Gruvbox, Kanagawa, Everforest,
Nord, Osaka Jade, Rose Pine, Matte Black, and Ristretto.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Drop the extra themes chapter from the manual

The community theme gallery will live elsewhere. Removes the chapter
and its 114 gallery images, renumbers the following chapters, and
repoints the two references (theme installs still work via
Install > Style > Theme in the menu).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Reference the shipped theme previews instead of copying them

The themes chapter now points straight at themes/*/preview.png and
preview-unlock.png, so previews can never drift from the source and
manual/images drops from 6.3MB to 3.5MB.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

manual/50-dual-boot-install.md

@@ -0,0 +1,44 @@
+# Dual Boot Install
+
+You're able to install Omarchy to a single partition alongside Windows or other installations.
+
+This installation method still comes with LUKS encryption for the partition by default so it's effectively no different than full drive and simply requires free space to be available on the disk.
+
+## Making Space on Windows
+
+To install alongside Windows, type `disk management` in the start menu and select the option for **Create and format hard disk partitions**.
+
+ ![dual-boot-1](images/dual-boot-1.webp)
+
+Find the appropriate partition, right click, and choose **Shrink Volume**.
+
+![dual-boot-2](images/dual-boot-2.webp)
+
+ Input the amount you'd like to shrink the volume by. Note that this will be the size of your future Omarchy install inclusive of the boot partition.
+
+ ![dual-boot-3](images/dual-boot-3.webp)
+
+When you're finished, you should see something like this where the 50GB section is where we'll install Omarchy in this example.
+
+ ![dual-boot-4](images/dual-boot-4.webp)
+
+## Installing Omarchy
+
+The install process for Omarchy is effectively the same as normal. After you select your disk, you'll be given the option of **Free space install**. Select that option to prevent wiping the full disk.
+
+ ![dual-boot-5](images/dual-boot-5.webp)
+
+Confirm that everything looks good and wait for the install to finish like normal. This is also where you could elect to install unencrypted (not recommended) just like on a full-drive install.
+ ![dual-boot-6](images/dual-boot-6.webp)
+
+## Adding Other Installs to the Bootloader
+
+When you finish your Omarchy install, you'll notice that the Limine bootloader is the default now. With this, you can also add options to Limine for your other installs such as Windows.
+
+In order to do that, run `limine-scan` and follow the prompts to add whichever items you'd like to your limine config. Then when you boot, you'll see your normal options for Omarchy, as well as Windows Boot Manager or others.
+
+## Bitlocker
+
+It's important to note that this install method is not compatible with Bitlocker as it encrypts the entire drive, not just the partition. If you encounter an error stating that Bitlocker is enabled, boot to Windows, go to **Settings -> Privacy & Security -> Device encryption** and toggle Bitlocker off. It may take some time to decrypt the drive.
+
+ ![dual-boot-7](images/dual-boot-7.webp)