Graph minimap can hide graph pieces when zoomed out

### Description

Here, I can't actually uncover the basic block by scrolling it to the right, since the margin of the scrollable area is calibrated for the size of the minimap when at 100% zoom.

### Steps to reproduce the bug

- zoom out

### Environment

```
angr environment report
=============================
Date: 2025-07-24 18:50:11.785103
Running in virtual environment at /home/audrey/proj/angr/.venv
Platform: linux-x86_64
Python version: 3.12.11 (main, Jun 3 2025, 15:41:47) [GCC 14.3.0]
######## angr #########
Python found it in /home/audrey/proj/angr/angr/angr/__init__.py
Pip version 9.2.167.dev0
Git info:
Current commit af1c424e16bbc41386c7154331a5bbdcd7389392 from branch feat/outlining
Checked out from remote emo: git@github.com:emolabs/angr
######## ailment #########
Python found it in None
Pip version not found!
Git info:
Current commit d4b115b6b5c886c623853f0c3ad08621e02e0242 from branch master
Checked out from remote origin: git@github.com:angr/angr-dev
######## cle #########
Python found it in /home/audrey/proj/angr/cle/build/__editable__.cle-9.2.167.dev0-py3-none-any/cle/__init__.py
Pip version 9.2.167.dev0
Git info:
Current commit 63a1028f786084c2803b8eab4877324664b5ca82 from branch master
Checked out from remote origin: git@github.com:angr/cle
######## pyvex #########
Python found it in /home/audrey/proj/angr/pyvex/pyvex/__init__.py
Pip version 9.2.167.dev0
Git info:
Current commit 1bd8938bfddd7fb397cc5be06882b9ac3045af17 from branch master
Checked out from remote origin: git@github.com:angr/pyvex
######## claripy #########
Python found it in /home/audrey/proj/angr/claripy/build/__editable__.claripy-9.2.167.dev0-py3-none-any/claripy/__init__.py
Pip version 9.2.167.dev0
Git info:
Current commit 4fb0e51f13d65226735148f5e38a69df73be0b0c from branch master
Checked out from remote origin: git@github.com:angr/claripy
######## archinfo #########
Python found it in /home/audrey/proj/angr/archinfo/build/__editable__.archinfo-9.2.167.dev0-py3-none-any/archinfo/__init__.py
Pip version 9.2.167.dev0
Git info:
Current commit 81862abe93e53ac59f1101ac2c3db19fded79ed2 from branch master
Checked out from remote origin: git@github.com:angr/archinfo
######## z3 #########
Python found it in /home/audrey/proj/angr/.venv/lib/python3.12/site-packages/z3/__init__.py
Pip version 4.13.0.0
Git info:
Current commit d4b115b6b5c886c623853f0c3ad08621e02e0242 from branch master
Checked out from remote origin: git@github.com:angr/angr-dev
######## unicorn #########
Python found it in /home/audrey/proj/angr/.venv/lib/python3.12/site-packages/unicorn/__init__.py
Pip version 2.0.1.post1
Git info:
Current commit d4b115b6b5c886c623853f0c3ad08621e02e0242 from branch master
Checked out from remote origin: git@github.com:angr/angr-dev
######### Native Module Info ##########
angr:
unicorn:
pyvex: .FFILibrary object at 0x7f16e96b6c90>
z3:
```

### Additional context

Possible solutions:

- scale minimap with main area scale
- allow scroll some amount outside of the margins based on zoom level
- make minimap movable