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/v0.2.77.ts

@@ -0,0 +1,12 @@
+import { VersionInfo } from '@start9labs/start-sdk'
+
+export const v_0_2_77 = VersionInfo.of({
+  version: '0.2.77:0',
+  releaseNotes: {
+    en_US: 'Multi-tenant cloud mode (opt-in via the "Enable Multi-Tenant Mode" StartOS action): magic-link sign-in via StartOS System SMTP, per-user libraries, anonymous trial summaries before signup, per-user Keysat licenses. Lite settings panel + sign-in / sign-out chip for tenants; full operator UX preserved for admins. New PWA support — Add to Home Screen on iOS / Android installs Recap as a standalone app. Mobile polish: bigger touch targets, library sidebar closed by default, "What can I paste?" info popover with brand card. Single-mode installs are unchanged behaviorally; only label tweaks ("Recap credits" instead of "relay credits", "link" instead of "URL") apply.',
+  },
+  migrations: {
+    up: async ({ effects }) => {},
+    down: async ({ effects }) => {},
+  },
+})