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>

agent/CONVENTIONS.md

@@ -45,8 +45,8 @@ those, it probably shouldn't exist.
 - **Waybar:** new indicators self-gate (hidden when irrelevant), use
   named `writeShellScriptBin`s on PATH (so static configs can exec them
   by bare name), and are added to **both** the generated `waybar.nix`
-  config **and** every `waybar.jsonc` whole-swap — summer-day, summer-night
-  and executive-slate (the parity rule).
+  config **and** every `waybar.jsonc` whole-swap — summer-day, summer-night,
+  executive-slate and boreal (the parity rule).
 - **Theming:** every new visual surface consumes the palette from the
   state JSON. There is no second renderer to keep in sync — add the key
   to the JSON, consume it in the module.