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/adc/SARADC-FIX.md

@@ -1,14 +1,14 @@
-# SARADC — VERIFIED on warden-c8a3 (2026-08-25); the -22 was vref, not clk
+# SARADC: VERIFIED on warden-c8a3 (2026-08-25); the -22 was vref, not clk
 
 The rockchip_saradc probe failed `-22` NOT at clk_set_rate (no "failed to set
-adc clk rate" ever printed) but at `regulator_get_voltage(info->vref)` — with no
+adc clk rate" ever printed) but at `regulator_get_voltage(info->vref)`: with no
 `vref-supply` in DT the driver got a **dummy** regulator, and
 `regulator_get_voltage(dummy)` returns -EINVAL, which probe returns directly (so
 only the generic "probe failed with error -22" showed). The earlier
 clk-rv1106-divider theory was wrong (the divider is HIWORD settable, xin24m is
 registered; clk_set_rate would clamp, not fail).
 
-**Fix (DT only):** add the 1.8 V reference the vendor 86-panel uses —
+**Fix (DT only):** add the 1.8 V reference the vendor 86-panel uses:
 ```dts
 / { vcc_1v8: vcc-1v8 { compatible = "regulator-fixed"; regulator-name = "vcc_1v8";
       regulator-always-on; regulator-boot-on;
@@ -16,4 +16,4 @@ registered; clk_set_rate would clamp, not fail).
 &saradc { vref-supply = <&vcc_1v8>; status = "okay"; };
 ```
 **Evidence:** `iio:device0` (`ff3c0000.saradc`), `in_voltage0_raw=1023`,
-`in_voltage1_raw=246` — both channels read real analog values (the adc-keys path).
+`in_voltage1_raw=246`, both channels read real analog values (the adc-keys path).