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/v0.2.73.ts

@@ -0,0 +1,13 @@
+import { VersionInfo } from '@start9labs/start-sdk'
+
+export const v_0_2_73 = VersionInfo.of({
+  version: '0.2.73:0',
+  releaseNotes: {
+    en_US:
+      'Defensive unwrap of the relay SSE "done" event so the title fix actually works against pre-0.2.60 relays too. Backstory: relay 0.2.60 finally fixes the real root cause of the "Untitled" library bug — markComplete was double-nesting the SSE done event so `data.result.title` was undefined and the actual title lived at `data.result.result.title`. This Recap release detects BOTH shapes: if the incoming SSE event has `data.result.result` with one of the expected inner keys (transcript / analysis / title), Recap unwraps once. Otherwise it uses `data.result` as-is (the new flat shape from relay 0.2.60+). Backwards-compatible with any relay version. Net effect: a Recap install upgraded to this version reads titles correctly regardless of which relay version is running on the operator side.',
+  },
+  migrations: {
+    up: async ({ effects }) => {},
+    down: async ({ effects }) => {},
+  },
+})