Add multi-tenant cloud mode: self-serve purchase, credit metering, core-decoupling

Introduces RECAP_MODE=multi alongside single-mode self-host:
- Tenant auth + accounts (magic-link via System SMTP), per-tenant credit pool,
  anonymous trial minting with per-IP/-64 caps
- Self-serve Pro/Max purchase: inline Lightning (BTCPay) + card (Zaprite),
  prepaid 30-day periods, expiry-reminder emails
- Core-decoupling: relay owns cloud tier/expiry keyed by Recaps user-id
- SQLite (better-sqlite3) schema for multi-mode; filesystem unchanged for single
- StartOS actions/versions through 0.2.155

startos/versions/v0.2.112.ts

@@ -0,0 +1,13 @@
+import { VersionInfo } from '@start9labs/start-sdk'
+
+export const v_0_2_112 = VersionInfo.of({
+  version: '0.2.112:0',
+  releaseNotes: {
+    en_US:
+      "Make the Phase 1 'inline payment unavailable' diagnostic visible to all viewers (not just admin) while we trace why the new bolt11 path isn't lighting up on Grant's test rig. Tiny italic gray line at the bottom of the legacy-fallback polling view, says what needs to be fixed (relay version OR BTCPay API key scope). Will be removed once inline rendering is confirmed working everywhere.",
+  },
+  migrations: {
+    up: async ({ effects }) => {},
+    down: async ({ effects }) => {},
+  },
+})