Rename the display name from FeNigma to FEnigma

FEnigma contains the whole word "enigma" while still opening on Fe (iron),
matching IRON NEST; FeNigma only contained "nigma". The cost is that iron's
symbol is Fe, not FE.

Code paths are untouched: the Python package stays lowercase `fenigma`, and
the git remote URL is unchanged since the repository itself has not been
renamed. APP_ID moved too, which is safe -- it is only the GTK application
id, with no saved state derived from it.

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

assets/icons/README.md

@@ -1,7 +1,7 @@
 # Icons
 
 Extracted from the game's own `GameAssets/Assets/Texture2D` (gitignored,
-not redistributed as a whole), for reuse in FeNigma's UI rather than
+not redistributed as a whole), for reuse in FEnigma's UI rather than
 redrawing equivalents from scratch. Two source filenames had typos in
 the game files themselves ("Frendly_", "Refrence_Point_"), corrected
 here on copy; everything else keeps its original name.

install.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Set up FeNigma: a venv for the pip deps, plus checks for the system
+# Set up FEnigma: a venv for the pip deps, plus checks for the system
 # packages that can't come from pip (GTK4/libadwaita bindings, tesseract).
 set -euo pipefail
 cd "$(dirname "${BASH_SOURCE[0]}")"

run.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Launch FeNigma.
+# Launch FEnigma.
 set -euo pipefail
 cd "$(dirname "${BASH_SOURCE[0]}")"
 

src/fenigma/__init__.py

@@ -1 +1 @@
-"""FeNigma: screen-reading helper for IRON NEST: Heavy Turret Simulator."""
+"""FEnigma: screen-reading helper for IRON NEST: Heavy Turret Simulator."""