docs: factual-drift pass + i2c option docs (#47, #48)

Fix documentation drift (each claim verified against code): theme count
21→24; waybar whole-swap lists (waybar.css=5 incl. neon-glass vs
waybar.jsonc parity=4 + boreal); idle "suspend 30"→"15 min battery-only";
Tailscale sudo→operator; hosts/live.nix "No installer yet" header; link
docs/MIGRATION.md + fix its placeholder URL; README layout tree
(+doctor/control-center/battery-notify); OVERRIDES swappy→satty; document
always-on home pieces. String fixes: keybind cheatsheet
nmtui→networkmanager_dmenu; complete nomarchy-menu usage string
(+doctor/firmware/controlcenter/rollback). Add README rows for
nomarchy.hardware.i2c.* (#48) — closes checks.option-docs.

Implemented by a worktree agent; diff reviewed and cherry-picked.
Verified V0 (flake check) + checks.option-docs green + V1 (HM build).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/TESTING.md

@@ -69,7 +69,7 @@ Work through these in order; each one exercises a different layer.
 | 2 | Waybar shows at top, themed (blue accent on dark) | HM waybar module, palette baking |
 | 3 | `SUPER+Return` opens Ghostty with the default theme colors (Boreal) | terminal default, ANSI palette |
 | 4 | `btop` in the terminal is themed | per-theme asset baking |
-| 5 | `nomarchy-theme-sync list` prints 21 presets | package, baked themes dir |
+| 5 | `nomarchy-theme-sync list` prints 24 presets | package, baked themes dir |
 | 6 | `nomarchy-theme-sync apply gruvbox` → state written, `home-manager switch` runs, desktop re-themes, wallpaper changes | the whole engine: state write, pure eval, HM rebuild, wallpaper hook |
 | 7 | `SUPER+SHIFT+T` cycles wallpapers instantly (try `tokyo-night` for 4, or `boreal` for its set) | the runtime wallpaper path |
 | 8 | `nomarchy-theme-sync apply summer-night` → after the switch the bar has its own identity (light bar, different styling) | whole-swap waybar.css assets |