docs: comments state what is, not how it came to be

The loader build, the gate script and the line-ending rule each carried the
story of their arrival - a measurement off the bench, a loop got wrong by
hand, a checkout reached from two hosts - where a sentence of what holds now
is enough. .gitattributes loses two patterns for files this repository does
not have, .clangd its two non-ASCII dashes, two headers a "per C" that read
as a stripped degree sign, and the README a "(new)" and the port's own
first attempt at stopping monitor.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CMakeLists.txt

@@ -37,14 +37,12 @@ add_custom_command(TARGET fantemp POST_BUILD
                    COMMAND ${CMAKE_OBJCOPY} -O ihex -R .eeprom
                            $<TARGET_FILE:fantemp> $<TARGET_FILE_DIR:fantemp>/fantemp.hex)
 
-# The board's loader, built here rather than named from memory: consuming
-# pureboot for its geometry alone left the one image this deployment cannot be
-# recovered without outside the repository that pins it. Every parameter is
-# pureboot's own default for this chip - USART0 at 115200 on the 16 MHz crystal
-# `src/board.hpp` declares - and that is measured rather than assumed, the
-# image being byte-for-byte the 386 B the board's slot reads back. It goes on
-# over the wire (`--update-loader`), which is why there is no flash target
-# beside it: no programmer has ever been in this board's path.
+# The board's loader, built from the pin, so the one image this deployment
+# cannot be recovered without is rebuilt by the commit that names it. Every
+# parameter is pureboot's own default for this chip - USART0 at 115200 on the
+# 16 MHz crystal `src/board.hpp` declares. It goes on over the wire
+# (`--update-loader`), which is why there is no flash target beside it: the
+# board has no programming header.
 pureboot_add_loader(pureboot)
 
 enable_testing()