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.

kernel/rv1106-enablement/configs/m2-earlycon.fragment

@@ -1,4 +1,4 @@
-# M2 earlycon config fragment for the RV1106 → Linux 6.18 forward-port.
+# M2 earlycon config fragment for the RV1106 -> Linux 6.18 forward-port.
 #
 # Base: multi_v7_defconfig (PORT-STATUS confirms it configures and CLK_RV1106
 # wires in cleanly). Apply this fragment on top, then `make olddefconfig`:
@@ -8,7 +8,7 @@
 #   make ARCH=arm CROSS_COMPILE=... olddefconfig zImage
 #
 # This builds an 11.8 MB zImage with our ported SoC drivers compiled in
-# (clk-rv1106.o, pinctrl-rockchip.o with the rv1106 data) — verified 2026-08-24.
+# (clk-rv1106.o, pinctrl-rockchip.o with the rv1106 data), verified 2026-08-24.
 
 # --- our ported RV1106 SoC drivers ---
 CONFIG_ARCH_ROCKCHIP=y