Add .bit nip-05 resolver via ElectrumX (namecoin)

[mstrofnone]

Resolve .bit NIP-05 identifiers via Namecoin

Adds a small .bit-suffix branch to alphaama's existing NIP-05 verification
path. Identifiers ending in .bit (e.g. m@something.bit, or bare
something.bit) get resolved against Namecoin via ElectrumX over WSS;
everything else still goes through NostrTools.nip05.queryProfile exactly
as today.

Why

Namecoin lets people anchor a Nostr identity to a name they actually own on
chain instead of one rented from a webserver. The wire format is small,
self-contained, and already in use by other Nostr clients (Amethyst,
Nostur, Jumble, nostrmo, and others — see references below). Wiring it
into alphaama is ~165 lines of vanilla JS, matches the scrappy style of
the codebase, and doesn't touch any existing call path that isn't a
.bit address.

How

Single new file: aa/fx/namecoin.js

• aa.fx.is_bit_nip05(s) — cheap suffix check, callers branch on it
• aa.fx.nip05_namecoin(s) — drop-in for nip05.queryProfile(s),
  returns {pubkey, relays} or null
• aa.fx.namecoin_resolve(key) — calls blockchain.name.show over wss,
  per-page TTL cache (5 min)
• aa.fx.electrumx_name_show(url, name) — one-shot wss JSON-RPC

Two hook points (one line each, default path unchanged):

• p/p.js aa.p.check_nip05 — backs the .p check <name@domain> CLI
  command and the click handler on the profile UI's NIP-05 row
• u/u.js setup flow — backs login by NIP-05 identifier

Server set

Browser-WSS subset of the canonical six ElectrumX servers, mirroring
Amethyst's DEFAULT_ELECTRUMX_SERVERS:

host	wss port
electrumx.testls.space	50004
nmc2.bitcoins.sk	57004
relay.testls.bit	50004
electrum.nmc.ethicnology.com	50004

Tried in order, first non-null wins, 5-minute cache. Bare-IP entries from
the canonical set are skipped because browser WSS needs SAN-matched certs
— they'd need TLSA TOFU pinning (separate NIP-track work) to be usable
from a browser.

Wire format

Covers the three nostr value shapes specified by ifa-0001 Domain Name
Object (already deployed on-chain by multiple identities today):

// shape 1: bare pubkey
{"nostr": "<hex64>"}

// shape 2: single id with optional relays
{"nostr": {"pubkey": "<hex64>", "relays": ["wss://...", ...]}}

// shape 3: names directory
{"nostr": {"names": {"alice": "<hex64>", ...}, "relays": [...]}}

Plus shallow one-hop import walking (keeps the implementation tight —
deep walking is unnecessary for the common case) and map sub-label
descent for subdomain.<name>.bit style identifiers. Tries d/<name>
first, then id/<name>.

Style notes

This matches alphaama's scrappy style — minimum viable resolver, ~165
lines incl. comments, single file, hangs off the global aa.* namespace,
snake_case, Allman braces, no build step, no module dance. Could have
been a n/ module with a mk.js and a CLI command set, but that would
be three times the code for the same behaviour. Happy to expand if you'd
rather have it as a proper module.

Verifying

.p check mstrofnone.bit

(any .bit name with a nostr field will work — current testers include
mstrofnone.bit, testls.bit, and several others on the chain today).

Diff

+219 / -3 across 4 files:

• aa/fx/namecoin.js (new, +219)
• aa/aa.js (+1 — adds the new fx file to the load list)
• p/p.js (+4, -2 — .bit branch in check_nip05)
• u/u.js (+2, -1 — .bit branch in setup)

References (cross-client wire-format precedent)

• nostr-tools PR nbd-wtf/nostr-tools#533 (open)
• jumble PR CodyTseng/jumble#774 (open)
• nostrudel PR hzrd149/nostrudel#352 (open)
• ants PR dergigi/ants#281 (open)
• nostrmo PR haorendashu/nostrmo#33 (open)
• nostur PR nostur-com/Nostur#60 (merged)
• dart-nostr PR ethicnology/dart-nostr#44 (merged)
• Amethyst (Kotlin/Android reference): DEFAULT_ELECTRUMX_SERVERS in
  quartz/.../nip05DnsIdentifiers/namecoin/ElectrumXServer.kt