Add NIP-11 limitation field to relay info document

[KTibow]

The relay's NIP-11 response was missing the limitation block entirely.
Since this is a Web-of-Trust relay that rejects events from untrusted pubkeys, it should use this standard format to communicate that it's locked down.

Change

Added a Limitation field to the RelayInformationDocument in main.go:

Limitation: &nip11.RelayLimitationDocument{
    MaxMessageLength: 512000,
    MaxLimit:         500,
    DefaultLimit:     500,
    AuthRequired:     false,
    PaymentRequired:  false,
    RestrictedWrites: true,
},

Evidence

restricted_writes: true

Once the trust network is built, only pubkeys in it may write events:

rg -n "not in web of trust" /tmp/wot-relay/
main.go:188:		return true, "not in web of trust"

rg -n "trusted := trustNetworkMap" /tmp/wot-relay/
main.go:174:		trusted := trustNetworkMap[pkHex]
main.go:773:	trusted := trustNetworkMap[ev.PubKey.Hex()]

max_message_length: 512000

Khatru's NewRelay() sets MaxMessageSize: 512000, which is applied via ws.conn.SetReadLimit(rl.MaxMessageSize). The wot-relay never overrides it.

rg -n "MaxMessageSize" /tmp/nostrlib/khatru/relay.go
55:		MaxMessageSize: 512000,
126:	MaxMessageSize          int64         // Maximum message size allowed from peer.

rg -n "SetReadLimit" /tmp/nostrlib/khatru/handlers.go
130:		ws.conn.SetReadLimit(rl.MaxMessageSize)

max_limit: 500

UseEventstore is called with 500:

rg -n "UseEventstore" /tmp/wot-relay/
main.go:164:	relay.UseEventstore(db, 500)

In khatru, maxQueryLimit is passed to QueryStored as maxLimit:

rg -n "func.*UseEventstore" /tmp/nostrlib/khatru/relay.go
138:func (rl *Relay) UseEventstore(store eventstore.Store, maxQueryLimit int) {

In the LMDB query engine, maxLimit caps the emitted count:

rg -n "totalEventsEmitted == limit" /tmp/nostrlib/eventstore/lmdb/query.go
170:			if totalEventsEmitted == limit {

default_limit: 500

When a filter has no limit, GetTheoreticalLimit() returns math.MaxInt, so maxQueryLimit (500) is the effective cap.

rg -n "return math.MaxInt" /tmp/nostrlib/filter.go
195:	return math.MaxInt

auth_required: false

No auth policy is installed:

rg -n "MustAuth" /tmp/wot-relay/
(no results)

payment_required: false

No payment infrastructure:

rg -n "Fees|PaymentsURL|payments_url|PaymentRequired|payment_required" /tmp/wot-relay/
(no results)

Fields deliberately omitted

None of these have code-enforced limits — using omitempty to leave them absent is correct:

Field	Reason
max_subscriptions	addListener() appends to []listenerSpec with no capacity check
max_subid_length	Subscription IDs stored as-is, no length validation
max_event_tags	PreventTooManyIndexableTags exists in khatru but is not wired in main.go
max_content_length	PreventLargeContent exists in khatru but is not wired in main.go
min_pow_difficulty	No PoW check; omitempty drops the zero value
created_at_lower_limit	PreventTimestampsInThePast is not wired; deleteOldNotes() is post-hoc cleanup
created_at_upper_limit	PreventTimestampsInTheFuture is not wired

Confirmed via:

rg -n "PreventLargeContent|PreventTooManyIndexableTags|PreventTimestampsIn|RestrictToSpecifiedKinds" /tmp/wot-relay/
(no results)