discovery: caller-ID popup for delivery orders #1343

Parent: #830 (S4). Discovery / needs design. Verified against main @ 8e39053.

Problem

Delivery-heavy stores want an incoming phone call to pop up the caller's customer record on the POS and start a delivery order (Sami, 4 and 8 Sep).

Current behavior (verified)

Nothing exists. caller.?id|incoming.?call|telephony|sip:|asterisk returns 0 hits in main, shared, frontend/src and docs. Delivery orders, customer phone lookup (including trunk-zero matching, #1119) and courier slips already exist.

First step (before any code)

Ask Sami (and other delivery stores) what phone setup they use:

• landline with a USB caller-ID modem
• VoIP / SIP PBX (which one?)
• mobile phone (Android)
• country and number format

Candidate approaches (pick after discovery)

1. SIP/VoIP webhook: the PBX posts the caller number to a LAN endpoint on the API (:3001). Simplest, if they have a PBX.
2. USB CID modem: the main process reads serial caller-ID frames. Hardware and driver work per OS.
3. Android companion: the phone forwards incoming numbers over LAN. This would live in RevFlo (proprietary) and talk through the existing pairing.

Common pieces regardless of source

• Ingest endpoint and auth (paired device token).
• Phone lookup via the customers route, and a push to POS clients.
• Popup: "Caller: name, last order, address", plus a "Start delivery order" action that pre-fills the cart.
• Must work offline on the LAN (offline-first invariant).

Acceptance (for discovery)

• A comment here lists the hardware or PBX in use and a chosen approach. Then convert this issue to a feature with acceptance criteria.