refactor(rename): root + flake output names → bitSpire/bitspire

Three root-level identifier renames:

  - Root package.json `name`:  lamassu-next  → bitSpire
  - flake.nix nixosConfigurations.lamassu-live-*: kept (legacy
    aliases) and ADDED bitSpire-live-* alongside. Both work.
    Drop the lamassu-* aliases at the final cutover once nothing
    references them.
  - nix/mkAtmApp.nix `pname`:  lamassu-atm-app → bitspire-atm-app
    (lowercase to match nix package naming conventions; the
    Electron app's externally-facing names get their own commit).

What's NOT renamed here (per the plan):

  - Hardware-named outputs (douro, tejo, sintra, batm3) — those
    are physical product names.
  - nixosConfigurations.{douro,tejo,sintra,batm3} ergonomic
    aliases — same reason.
  - nixosModules.lamassu-atm + its imported file — that's the
    systemd service, deferred to 2d.
  - apps/machine/package.json appId/productName — Electron
    identity, deferred to 2c.

Verified:
  pnpm typecheck         clean (12/12 cached)
  nix eval .#nixosConfigurations.bitSpire-live-sintra ✓
  nix eval .#packages.x86_64-linux.atm-app-sintra.pname ✓
  → "bitspire-atm-app"

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

nix/mkAtmApp.nix

@@ -24,7 +24,7 @@ let
   };
 in
 pkgs.stdenv.mkDerivation (finalAttrs: {
-  pname = "lamassu-atm-app";
+  pname = "bitspire-atm-app";
   version = "0.1.0";
 
   inherit src;