feat: ship fresh nodes with default trusted Cashu mints

cashu_mints previously defaulted to an empty list, leaving a new node in a
half-working state: it silently trusted the hardcoded minibits primary mint
but advertised no mints in /v1/info or its NIP-91 listing, so clients
discovering the node had no way to know where to pay.

- default cashu_mints to minibits + cubabitcoin via shared DEFAULT_CASHU_MINTS
- reuse the constant for the primary_mint fallback (removes duplicate literal)
- CASHU_MINTS env or dashboard edits still replace the list entirely; an
  explicitly empty value keeps only the primary mint trusted
- document the defaults in configuration.md, dashboard.md, .env.example

Existing nodes are unaffected: the settings-blob merge skips persisted empty
lists, so unconfigured nodes pick up the defaults on restart while nodes with
explicit mints keep theirs.

.env.example

@@ -45,6 +45,7 @@ ROUTSTR_SECRET_KEY=
 # ONION_URL=http://mynode.onion (auto fetched from compose)
 # RELAYS="wss://relay.damus.io,wss://relay.nostr.band,wss://eden.nostr.land,wss://relay.routstr.com"
 # ENABLE_ANALYTICS_SHARING=true
+# CASHU_MINTS="https://mint.minibits.cash/Bitcoin,https://mint.cubabitcoin.org"  # this is the default
 # CASHU_MINTS="https://mint.minibits.cash/Bitcoin,https://mint.cubabitcoin.org,https://ecashmint.otrta.me"
 # MINT_OPERATION_CONCURRENCY=4
 # MINT_OPERATION_TIMEOUT_SECONDS=30

docs/provider/configuration.md

@@ -139,6 +139,15 @@ Which mints to accept payments from:
 | --------- | ------------------------------- |
 | **Mints** | List of trusted Cashu mint URLs |
 
+A fresh node ships with two mints preconfigured:
+
+- `https://mint.minibits.cash/Bitcoin`
+- `https://mint.cubabitcoin.org`
+
+Setting `CASHU_MINTS` (env) or editing the list in the dashboard replaces this
+default entirely. An explicitly empty value leaves only the primary mint
+trusted.
+
 ### Lightning Withdrawals
 
 Automatic profit withdrawal:
@@ -197,7 +206,7 @@ Use environment variables for:
 | `NPUB`               | Nostr public key (bech32)         | —                                    |
 | `NSEC`               | Legacy seed for the Nostr private key (otherwise set from the admin UI) | —                |
 | `ENABLE_ANALYTICS_SHARING` | Enable usage analytics sharing to Nostr | `true`                         |
-| `CASHU_MINTS`        | Comma-separated mint URLs         | `https://mint.minibits.cash/Bitcoin` |
+| `CASHU_MINTS`        | Comma-separated mint URLs         | `https://mint.minibits.cash/Bitcoin,https://mint.cubabitcoin.org` |
 | `MINT_OPERATION_CONCURRENCY` | Concurrent mint/unit balance reads | `4` |
 | `MINT_OPERATION_TIMEOUT_SECONDS` | Per-attempt timeout for mint network calls | `30` |
 | `MINT_MAX_CONCURRENCY` | Concurrent operations allowed per mint (`0` disables the limit) | `4` |

docs/provider/dashboard.md

@@ -132,7 +132,9 @@ Connect to your AI provider:
 
 ### Cashu Mints
 
-Manage which mints you accept payments from:
+Manage which mints you accept payments from. A fresh node comes with two
+default mints preconfigured (`https://mint.minibits.cash/Bitcoin` and
+`https://mint.cubabitcoin.org`):
 
 - **Add Mint** — Enter a mint URL
 - **Remove Mint** — Stop accepting from a mint

routstr/core/settings.py

@@ -11,6 +11,14 @@ from typing import Any
 from pydantic.v1 import BaseModel, BaseSettings, Field
 from sqlmodel.ext.asyncio.session import AsyncSession
 
+# Mints a fresh node trusts out of the box, shared by the settings default and
+# the primary-mint fallback. Defined before the Settings class because the
+# default_factory lambda resolves it at class-definition time.
+DEFAULT_CASHU_MINTS: list[str] = [
+    "https://mint.minibits.cash/Bitcoin",
+    "https://mint.cubabitcoin.org",
+]
+
 
 class Settings(BaseSettings):
     class Config:
@@ -37,7 +45,12 @@ class Settings(BaseSettings):
     onion_url: str = Field(default="", env="ONION_URL")
 
     # Cashu
-    cashu_mints: list[str] = Field(default_factory=list, env="CASHU_MINTS")
+    # Mints a fresh node trusts out of the box. Setting CASHU_MINTS (env or
+    # dashboard) replaces this list entirely; an explicitly empty value yields
+    # an empty list (no trusted mints beyond primary_mint).
+    cashu_mints: list[str] = Field(
+        default_factory=lambda: list(DEFAULT_CASHU_MINTS), env="CASHU_MINTS"
+    )
     receive_ln_address: str = Field(default="", env="RECEIVE_LN_ADDRESS")
     primary_mint: str = Field(default="", env="PRIMARY_MINT_URL")
     primary_mint_unit: str = Field(default="sat", env="PRIMARY_MINT_UNIT")
@@ -256,7 +269,7 @@ def _apply_to_live_settings(data: dict[str, Any]) -> None:
 
 
 def _compute_primary_mint(cashu_mints: list[str]) -> str:
-    return cashu_mints[0] if cashu_mints else "https://mint.minibits.cash/Bitcoin"
+    return cashu_mints[0] if cashu_mints else DEFAULT_CASHU_MINTS[0]
 
 
 def derive_npub_from_nsec(nsec: str) -> str | None: