Desktop Helper Pairing — draft set

DRAFT ARTIFACTS. This folder is design-time scaffolding for pairing the Peach browser extension (Solid.js + TypeScript) with the peach-sync desktop helper, then syncing the vault to it over the LAN. Nothing here is wired into the build. On apply, follow INTEGRATION-CONTRACT.md and then the whole folder can be removed (use trash, never rm).

What this is

A six-change plan, each pinned to verified source in both repos (peach-browser and peach-sync):

1. Change 1 — send vault_id in the PAIR_IDENTITY frame so the helper records which vault it paired to.
2. Change 2 — "desktop" DeviceType (already present — no-op).
3. Change 3 — background code-pairing client (desktop-pairing.ts).
4. Change 4 — popup pairing UI (DesktopPairingFlow.tsx).
5. Change 5 — handshake-free subnet port probe for the pairing port.
6. Change 6 — include "desktop" peers in sync sessions (one-line filter widening — not a no-op as first assumed; see below).

Corrected premises vs the original brief

The brief was written before reading the source. These premises were wrong and are corrected throughout the draft set (binding pin: _GROUND-TRUTH.md):

Brief said	Reality (verified)
Add "desktop" to DeviceType in src/shared/types.ts	"desktop" already in src/shared/sync-types.ts:11; types.ts has no DeviceType. Change 2 is a no-op.
Helper acks with PEACH_HELLO_OK	It's PEACH_HELLO_ACK (pairing.zig:40). No _OK frame exists.
Helper sends PEACH_HELLO_ERROR on wrong code	No error frame. Wrong/expired code → silent socket close + code rotation (pairing.zig:117,119-125).
(implied) browser is NK responder	For desktop pairing the browser is the NK initiator (pairing.zig:153-154) — opposite of the audio-chirp flow.
React, hooks, PeachField, OutlinedTextField	Repo is Solid.js. No PeachField component — it's a <input class="peach-underline-input">. Tests use renderView, not @solidjs/testing-library.
Bump 4.0.1 → 4.0.2	Dev is already 4.0.2. Integration bumps 4.0.2 → 4.0.3.
Sync port assumption	Sync server is 8765 (Noise XX); pairing server is 49142 (Noise NK). Both verified.
Change 6 just works	Runner/coordinator are generic, but sync-trigger.ts:104 filters to `android
derivePairingSas (lowercase)	Existing export is derivePairingSAS (capital). Reuse it.
SAS KAT 0fbab8cd… → 895245	Correct — confirmed against pairing.zig:275-279.
{ accept: true } on confirm	Canonical payload is { confirmed: boolean } (03 + 04).

Reading order

1. _GROUND-TRUTH.md — the binding wire contract. Read first.
2. 01-vault-id-in-pair-identity.md
3. 02-desktop-device-type.md (no-op verification)
4. 05-subnet-probe.md (Change 3 depends on it)
5. 03-desktop-pairing-handler.md
6. 04-desktop-pairing-ui.md
7. 06-sync-coordinator-desktop.md
8. tests/ — the four companion spec files (26 specs total).
9. INTEGRATION-CONTRACT.md — the authoritative apply plan (file map, order, message contract, TODOs, version, quality bar). Read last, follow on apply.