deps: the pins advance, and this repository gets a committed gate

libavr moves to its USI I2C rate accounting, the two override surfaces the
fan-controller port filed - a PWM solve that can be pinned, a capture edge that
is a value - and the shared preset loop's own fix. pureboot moves with it. This
firmware names none of them and no image moved.

`tools/check.sh` is new, and its absence was the defect: there was no committed
gate at all, so "run the suite" was a snippet somebody remembered - and the
order in a snippet is the one thing nobody re-derives. Every preset built
before any is tested is subtle and load-bearing, because the mode-identity
check reads the sibling mode's tree and a build-then-test-per-preset run holds
a fresh image against a stale sibling. The loop is libavr's
`tools/check-presets.sh`.

Two defaults stop being the editing machine's. `.vscode/settings.json` named
`D:/dev/libavr/local/toolchain/avr-gcc-16.1.0-mingw`, which is a path true of
one machine (libavr guidance rule 50) and, since the in-repo toolchain copies
went, true of none - `local/machine.cmake` is where a checkout says that and it
already did. And `.gitattributes` gains `* text=auto eol=lf`: naming the source
extensions left Markdown, Python, shell and CMake to whatever wrote them, which
on the Windows side is CRLF, and a rewrite there buries the change it made.

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

.gitattributes

@@ -1,8 +1,11 @@
-*.h         eol=lf
+# Line endings are the repository's, not the editing machine's: this checkout
-*.hpp       eol=lf
+# is reached from two hosts, and a file rewritten by a Windows tool comes back
-*.c         eol=lf
+# with every line changed unless something says otherwise. Naming the source
-*.cpp       eol=lf
+# extensions left Markdown, Python, shell and CMake to whatever the writing
-.git*       eol=lf
+# tool defaulted to, which is CRLF on one of the two.
+* text=auto eol=lf
+
+# Atmel Studio writes these and expects them back.
 *.vcxproj*  eol=crlf
 *.cppproj   eol=crlf
 *.sln       eol=crlf

.vscode/settings.json

@@ -11,14 +11,13 @@
 		"--header-insertion=never"
 	],
 
-	// The presets are the build interface; the toolchain file inside the
+	// The presets are the build interface, and the toolchain file inside the
-	// libavr submodule is the one place the compiler is chosen. The submodule
+	// libavr submodule is the one place the compiler is chosen. **No prefix is
-	// carries no local/toolchain for it to discover, so the prefix is named
+	// named here**: a committed file may not name a path that is true of one
-	// here, for the window that opens this folder.
+	// machine (libavr guidance rule 50), so the gitignored local/machine.cmake
+	// at this repository's root is where a checkout says where its toolchain
+	// is - one file, and it answers for both hosts.
 	"cmake.useCMakePresets": "always",
-	"cmake.environment": {
-		"LIBAVR_TOOLCHAIN": "D:/dev/libavr/local/toolchain/avr-gcc-16.1.0-mingw"
-	},
 	"cmake.configureOnOpen": true,
 	"cmake.options.statusBarVisibility": "compact",
 

tools/check.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# The task gate: every configure preset built, and only then every one tested.
+#
+# The loop itself is libavr's (tools/check-presets.sh) because the order in it
+# is subtle and was got wrong by hand more than once - the mode-identity checks
+# read the sibling mode's tree, so a build-then-test-per-preset run compares a
+# fresh image against a stale sibling. Anything this repository needs beyond
+# the presets is written after the call, where every tree is built and tested.
+set -euo pipefail
+cd "$(dirname "${BASH_SOURCE[0]}")/.."
+"${LIBAVR_ROOT:-libavr}/tools/check-presets.sh" "$@"