docs: finish the LNbits-era doc sweep across docs/ + .claude/skills/

Second + final batch of the doc refresh. README + CLAUDE went out in
8c9ae29; deploy/nixos/README + obsolete-flow flags in 924844f. This
commit covers everything left.

docs/machine-installation.md
  Was describing a manual AppImage scp deploy + a `lamassu-kiosk`
  systemd unit that hasn't been the deployment path for months.
  Replaced with a high-level "what the pipeline does and why"
  overview that points at deploy/nixos/README.md for the full
  command-by-command walkthrough. Includes the BATM3 chassis-mod
  note (custom Dell OptiPlex retrofit, not a stock Dell).

docs/architecture-comparison.md
  Rewrote the comparison to be lamassu-server (≤ v8.1.5) vs bitSpire
  (LNbits-backed) instead of the original lamassu-server vs LP-backed
  lamassu-next framing. Updated the cash-out + cash-in flow diagrams
  to show the actual nostr-transport path (LNbits-bundled nostrrelay
  extension at ws://<host>:5001/nostrrelay/test, no separate strfry
  container). Replaced the migration-path section with a softer
  "when to choose what" framing that includes Lamassu's current
  commercial offering as a legitimate third option. Added a header
  pointer to the Acknowledgements section.

docs/business-model.md
  Light touch-ups: Lightning.Pub → LNbits where it appeared, swapped
  the [[ndebit-cash-in-flow]] link for [[architecture-comparison]],
  noted the kind-30078 service beacon for availability broadcasts.

docs/device-configuration.md
  Dropped "Lamassu" branding from the machine-model headings
  (Sintra / tejo / douro / batm3 are referenced by hardware identity
  here, not by Lamassu's product line). Added the Sintra-specific
  ttyS4-vs-placeholder-ttyS1..3 gotcha we hard-learned during the
  first flash. Corrected the BATM3 entry: stock GeneralBytes chassis
  with a Dell OptiPlex 9030 AIO motherboard physically grafted in,
  NOT a Dell out of the box. Updated the example /dev/ttyJ* symlink
  output to match what a healthy Sintra actually shows.

docs/adr/001-hal-architecture.md
  ADRs are historical artifacts — kept the original decision text
  intact. Added a postscript noting:
    - The package rename @lamassu/hal → @bitSpire/hal
    - The v8.1.5 boundary on any lamassu-machine source-tree
      references (Lamassu's 2024-01-26 license transition)
    - That the "Remaining Work" list is complete and the first
      successful Sintra hardware integration ran on 2026-05-13

.claude/skills/lightning-check.md
  Rewrote end-to-end. Was Lightning.Pub-flavoured with CLINK kinds
  21001/21002 as the primary flows; now validates the LNbits nostr-
  transport surface (kind-21000 envelope, NIP-44 v2 encryption,
  subscribe_payments filter discipline, lnurlw link composition).
  Preserved a --clink mode for the still-live kind-21003 operator-
  management surface. Includes a "what to check" rubric for cash-out
  vs cash-in flows that mirrors the actual code in
  apps/machine/src/services/lightning.ts.

.claude/skills/hal-check.md
  Two pivots: (1) acknowledge ADR-001's TypeScript-not-Rust choice
  and reframe all the safety checklists in TS-flavour (type safety,
  discriminated unions, single-writer serial, bounded emitters)
  instead of Rust-flavour (unsafe, borrow checker). (2) Add explicit
  v8.1.5 provenance boundary plus a "forbidden operations" section
  that prohibits diffing or porting from v8.1.6+ lamassu-machine
  source. Updated the port-validation source-reference table to
  list TS file paths under packages/hal/ instead of Rust paths.

.claude/skills/docs.md
  @lamassu/* → @bitSpire/*. Replaced the Lightning.Pub mermaid
  diagram with a current cash-out flow showing the nostr-transport
  RPC + subscribe_payments push path. Left the createOffer noffer
  example in the API-docs template section since it's illustrative
  ("here's what a good TSDoc block looks like") rather than current
  reference documentation.

.claude/skills/test.md
  One-line: @lamassu/nostr-client → @bitSpire/nostr-client in the
  pnpm-filter example.

deploy/nixos/README.md
  Single touch-up: clarified the douro/batm3 hardware-module comments
  to reflect that BATM3 is a custom-installed Dell board in a
  GeneralBytes BATM3 chassis (not a Dell OEM).

Files NOT touched in this sweep (intentionally):
  - packages/hal/src/**/*.ts attribution comments — those reference
    "lamassu-machine" in their port-source headers. Those are
    factually accurate (the drivers ARE ported from there, up to
    v8.1.5) and constitute necessary license/attribution metadata.
    Editing them would erase the provenance trail.
  - .claude/skills/{nostr-check,security}.md — already protocol-
    neutral, no LP/lamassu references to clean up.

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

deploy/nixos/README.md

@@ -12,8 +12,8 @@ deploy/nixos/
 ├── configuration.nix       # Base system (NixOS 24.05, locale, kernel, packages, lamassu user)
 ├── live.nix                # Live USB variant (squashfs + tmpfs root) — used by mkLiveConfig
 ├── hardware/
-│   ├── douro.nix           # Dell OptiPlex 9030 AIO (batm3 sibling; SATA SSD, eGalax touch)
-│   ├── batm3.nix           # GeneralBytes BATM3 (Dell board, WireGuard wired in)
+│   ├── douro.nix           # Dell OptiPlex 9030 AIO (stock Douro motherboard; SATA SSD, eGalax touch)
+│   ├── batm3.nix           # GeneralBytes BATM3 chassis with a Dell OptiPlex 9030 AIO grafted in (custom mod; WireGuard wired in)
 │   └── upboard.nix         # Aaeon UP Board (Sintra + tejo; eMMC root via sdhci-acpi + mmc_block)
 ├── udev/
 │   └── 99-lamassu-hardware.rules    # additional udev rules (loaded via configuration.nix)