docs: ASCII typography and style normalization across all repo text

Replace every em dash with real punctuation (rewrites, not hyphen swaps)
in docs, code comments, scripts, configs, and the port records; convert
en dashes, curly quotes, ellipsis glyphs, arrows, and section signs to
ASCII; drop machine-writing tell phrases from living docs. ADR titles
now use a colon. The M2 bring-up DTS model string carried an em dash
into the patch series and its record echoes; fixed at both, and the full
series re-verified to apply cleanly onto pristine 6.18.46. One comment
in freshness.h deliberately names the em dash glyph the UI renders as
the unknown mark; that is data, kept as prose naming it.

Verified: cargo tests (sim, config-lint, rs485-bridge), shellcheck,
both driver MC/DC harnesses, patches-apply.

patches/20-arch-dts-bindings.patch

@@ -1835,7 +1835,7 @@ index 000000000..418652552
 +#include <dt-bindings/clock/rv1106-cru.h>
 +
 +/ {
-+	model = "WardenOS 86-Panel (RV1106) — M2 earlycon bring-up";
++	model = "WardenOS 86-Panel (RV1106), M2 earlycon bring-up";
 +	compatible = "rockchip,rv1106";
 +	#address-cells = <1>;
 +	#size-cells = <1>;