build: presets.generated runs, and the tier list lives in the sources

make_presets.py documented a presets.generated test that was never registered,
so a hand edit to CMakePresets.json could drift unseen; it is registered now,
and the generator names its encoding and line ending so a regeneration on
Windows writes the same file. The CMake comment's per-tier essay repeated each
source's own header - and claimed naked stubs where all four use
startup::entry - so it points there instead, and the flash size the boot base
and the wrap-around both follow from is named once.

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

tools/make_presets.py

@@ -75,12 +75,12 @@ def main():
     rendered = json.dumps(presets, indent=1) + "\n"
     path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "CMakePresets.json")
     if "--check" in sys.argv[1:]:
-        current = open(path).read() if os.path.exists(path) else ""
+        current = open(path, encoding="utf-8").read() if os.path.exists(path) else ""
         if current != rendered:
             print("CMakePresets.json does not match its generator - run tools/make_presets.py")
             return 1
         return 0
-    with open(path, "w") as f:
+    with open(path, "w", encoding="utf-8", newline="\n") as f:
         f.write(rendered)
     print(f"{len(CHIPS)} chips, {len(REFLECT_SPOT)} reflect: {os.path.normpath(path)}")
     return 0