Convergence on the Python resolver shape (PR #1795 `snrc-resolve.py`) so
a names router can be backed either by the direct-ETH-RPC resolver or by
the Python REST resolver without changing the wire format clients see.

Wire-level changes:

- Add `nickname`, `website`, `location`, `simplex.contact`,
  `simplex.channel`, `ETH`, `BTC`, `XMR`, `DOT`, `resolver` (SNRC
  contract address that produced the record); all but `name`, `owner`,
  `resolver` are optional.
- Drop `displayName` (now `name`), `channelLinks`, `contactLinks`,
  `adminAddress`, `adminEmail`, `expiry`, `isTest`.
- The wire NameRecord no longer carries `expiry`; clients trust the
  server's filter. Expiry checking moves into `decodeGetRecord`, which
  now takes a `nowSec :: Int64` argument (the placeholder remains, but
  the field-layout-aware decoder will apply the filter once it lands).
- Testnet status is derived from the queried TLD (`TLDTesting` vs
  `TLDSimplex`) rather than an in-record flag.

Other:

- ToJSON/FromJSON are hand-rolled because Aeson TH doesn't accommodate
  dot-keys (`simplex.contact`) or uppercase coin keys (`ETH`/`BTC`...).
- `NameLink` newtype is removed (no longer used internally); per-field
  byte caps are applied directly in the FromJSON parser.
- Update the canonical-encoding spec in protocol/simplex-messaging.md.

Replace the direct Ethereum JSON-RPC eth_call flow with HTTP calls to the
snrc-resolve.py REST resolver (PR #1795). The Python service owns the
on-chain registry mapping per TLD; the SMP server forwards each RSLV as
`GET /resolve/<name>` and parses the JSON response as a NameRecord.

Wire-format changes (no SMP version bump):

* RslvRequest.contract is now parsed but ignored server-side. The wire
  field is retained for forward compatibility with possible future
  eth-backed implementations. The agent sends a zero-address placeholder.
* NameRecord JSON keys match the Python resolver exactly: lowercase
  camelCase (simplexContact / simplexChannel) and lowercase coin keys
  (eth/btc/xmr/dot). Text fields use the empty string `""` as the unset
  sentinel; coin fields use JSON null.

Module changes:

* New: Simplex.Messaging.Server.Names.HttpResolver — http-client +
  redirect-disabled GET, body cap, optional Authorization header,
  scrubUrl extracted from the old eth/RPC module.
* Rewritten: Simplex.Messaging.Server.Names — HTTP backend with a
  ResolverCall test seam (replaces EthCall); ResolverCallKind tags
  fetch vs health probe so tests can assert routing. 404/400 map to
  NotFound; 5xx and transport failures map to ResolverError; decode
  errors to ResolverDecodeErr. parseName replaces verifyRslv (no more
  contract whitelist).
* Deleted: Simplex.Messaging.Server.Names.Eth.{RPC,SNRC} and
  Simplex.Messaging.SimplexName.Contracts — the ABI decoder, the
  Keccak namehash, and the TLD->contract whitelist are all owned by
  the Python resolver now.

Server-side flow:

* Server.hs's RSLV handler: parseName (instead of verifyRslv) + a
  single resolveName call (no contract argument).
* Env/STM.hs: pingEndpoint now hits `GET /health` (200 OK = ready).
* Main.hs INI keys renamed from `ethereum_endpoint` / `rpc_*` to
  `resolver_endpoint` / `resolver_*`. Dropped `rpc_max_concurrency`
  (http-client manages its own pool). Default
  `resolver_max_response_bytes` lowered to 65536 (the Python resolver's
  responses are ~2 KB; the previous 262144 was sized for ABI-encoded
  blobs). validateUrl SSRF hardening is preserved verbatim, only
  error messages and INI key names changed.

Agent side:

* resolveSimplexName' no longer consults `tldContract`; it passes a
  zero-address placeholder as RslvRequest.contract. The agent's public
  API is unchanged.

Spec doc updates:

* Backing store section: reference implementation forwards RSLV to the
  Python REST resolver; alternatives are valid as long as they expose
  the same HTTP shape or substitute a different transport.
* RslvRequest.contract documented as ignored / reserved.
* NameRecord field table updated: simplexContact (was simplex.contact),
  eth/btc/xmr/dot (was ETH/BTC/XMR/DOT), Text fields use empty string
  when unset (was nullable).

Tests:

* SMPNamesTests.hs: ABI decoder tests deleted; HTTP resolver tests
  added (success, 404, 400, 502, transport failure, malformed JSON,
  non-NameRecord JSON, health probe routing). 31 examples.
* RSLVTests.hs and AgentTests/ResolveNameTests.hs: switched from the
  eth-call stub to the resolver-call stub. The old INTERNAL "no
  resolver contract for TLD" branch is gone — TLDWeb now reaches the
  server and the resolver decides whether to honour it.