Clang 21 added -Wunterminated-string-initialization, which fails the
-Werror build when compiling secp256k1's intentionally non-null-terminated
bip340_algo[13] tag. Extend the existing macOS Clang warning suppression
with -Wno-error=unterminated-string-initialization.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

Cuts the per-glyph cost of FontManager.getFont(emoji=True) labels
from "C->Python round-trip per glyph" to "two int compares in C"
for any codepoint that isn't in the emoji map.

Why this matters: a Lightning Piggy transactions row, the Files
list, basically any label using a composed (emoji-fallback) font
is overwhelmingly ASCII. Today every glyph crosses into the
MicroPython _imgfont_path_cb just to return None, then LVGL
falls back to the base Montserrat. With LVGL's imgfont gaining a
codepoint accept/exclude range, codepoints outside the emoji
range are rejected in C and skip the Python callback entirely;
LVGL falls back to the base font at C speed. Emoji codepoints
still hit the Python path (unchanged).

Three pieces:

* internal_filesystem/lib/mpos/ui/font_manager.py
  - _create_emoji_font(size) now calls
    lv.imgfont_set_range(font, cp_min, cp_max, 0xE000, 0xF8FF)
    after creating the imgfont. cp_min/cp_max are computed
    dynamically from the loaded _emoji_maps keys (so the filter
    self-maintains as the emoji set grows — no hardcoded magic).
  - Guarded by try/except AttributeError, so a build whose
    pinned lvgl_micropython SHA predates the patch keeps working,
    just without the speedup.

* scripts/build_mpos.sh
  - Applies lvgl_micropython/imgfont_set_range.patch into
    lib/lvgl during the build, gated by a -f existence check so
    older lvgl_micropython pins (no patch file present) still
    build cleanly.

* lvgl_micropython submodule bump
  - 916ec6b -> e00d9d9, picks up the new imgfont_set_range.patch
    plus a small unrelated brew-config parser fix in
    builder/macOS.py that was breaking macOS builds entirely.

Verified end-to-end on Waveshare ESP32-S3-Touch-LCD-2 (macOS
desktop build also OK). FontManager.getFont(emoji=True) on
device computes bounds (0x203C, 0x1F9E2) — exactly the actual
min/max across the loaded 400-emoji set. Scrolling the LP
transactions list is noticeably smoother than the pre-patch
build.

Backward-compat note: lvgl_micropython e00d9d9 is currently only
on bitcoin3us/lvgl_micropython. Submodule pointer here will
resolve once that branch lands on MicroPythonOS/lvgl_micropython;
.gitmodules intentionally still points at the upstream URL.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

Fast composed-font emoji rendering via lv_imgfont_set_range

build_mpos.sh: fix macOS build on Clang 21

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