Add session mode for pre-funded request processing

Implement session-based API endpoints for creating, managing, and interacting with pre-funded sessions, including deposit and top-up invoice generation, macaroon authentication, and per-request debiting of compute costs.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 418bf6f8-212b-4bb0-a7a5-8231a061da4e
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Replit-Commit-Event-Id: 2dc3847e-7186-4a22-9c7e-16cd31bca8d9
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Replit-Helium-Checkpoint-Created: true

lib/db/src/schema/index.ts

@@ -3,3 +3,4 @@ export * from "./invoices";
 export * from "./conversations";
 export * from "./messages";
 export * from "./bootstrap-jobs";
+export * from "./sessions";

lib/db/src/schema/sessions.ts

@@ -0,0 +1,101 @@
+import { pgTable, text, timestamp, integer, boolean, real } from "drizzle-orm/pg-core";
+import { createInsertSchema } from "drizzle-zod";
+import { z } from "zod/v4";
+
+// ── Session state machine ─────────────────────────────────────────────────────
+
+export const SESSION_STATES = [
+  "awaiting_payment",
+  "active",
+  "paused",
+  "expired",
+] as const;
+export type SessionState = (typeof SESSION_STATES)[number];
+
+export const SESSION_REQUEST_STATES = [
+  "processing",
+  "complete",
+  "rejected",
+  "failed",
+] as const;
+export type SessionRequestState = (typeof SESSION_REQUEST_STATES)[number];
+
+// ── sessions ──────────────────────────────────────────────────────────────────
+
+export const sessions = pgTable("sessions", {
+  id: text("id").primaryKey(),
+  state: text("state").$type<SessionState>().notNull().default("awaiting_payment"),
+
+  balanceSats: integer("balance_sats").notNull().default(0),
+  depositAmountSats: integer("deposit_amount_sats").notNull(),
+
+  // Deposit invoice (stored inline — avoids FK into jobs table)
+  depositPaymentHash: text("deposit_payment_hash").notNull(),
+  depositPaymentRequest: text("deposit_payment_request").notNull(),
+  depositPaid: boolean("deposit_paid").notNull().default(false),
+
+  // Current topup invoice (one at a time; all nullable until created)
+  topupAmountSats: integer("topup_amount_sats"),
+  topupPaymentHash: text("topup_payment_hash"),
+  topupPaymentRequest: text("topup_payment_request"),
+  topupPaid: boolean("topup_paid"),
+
+  // Auth token — issued once when session activates; required for requests
+  macaroon: text("macaroon"),
+
+  // TTL — refreshed on each successful request
+  expiresAt: timestamp("expires_at", { withTimezone: true }),
+
+  createdAt: timestamp("created_at", { withTimezone: true }).defaultNow().notNull(),
+  updatedAt: timestamp("updated_at", { withTimezone: true }).defaultNow().notNull(),
+});
+
+export const insertSessionSchema = createInsertSchema(sessions).omit({
+  createdAt: true,
+  updatedAt: true,
+});
+
+export type Session = typeof sessions.$inferSelect;
+export type InsertSession = z.infer<typeof insertSessionSchema>;
+
+// ── session_requests ──────────────────────────────────────────────────────────
+
+export const sessionRequests = pgTable("session_requests", {
+  id: text("id").primaryKey(),
+  sessionId: text("session_id")
+    .notNull()
+    .references(() => sessions.id),
+  request: text("request").notNull(),
+  state: text("state")
+    .$type<SessionRequestState>()
+    .notNull()
+    .default("processing"),
+
+  result: text("result"),
+  reason: text("reason"),
+  errorMessage: text("error_message"),
+
+  // Eval token usage (Haiku judge)
+  evalInputTokens: integer("eval_input_tokens"),
+  evalOutputTokens: integer("eval_output_tokens"),
+
+  // Work token usage (Sonnet; null for rejected requests)
+  workInputTokens: integer("work_input_tokens"),
+  workOutputTokens: integer("work_output_tokens"),
+
+  // Balance debit for this request
+  debitedSats: integer("debited_sats"),
+  balanceAfterSats: integer("balance_after_sats"),
+  btcPriceUsd: real("btc_price_usd"),
+
+  createdAt: timestamp("created_at", { withTimezone: true }).defaultNow().notNull(),
+  updatedAt: timestamp("updated_at", { withTimezone: true }).defaultNow().notNull(),
+});
+
+export const insertSessionRequestSchema = createInsertSchema(sessionRequests).omit({
+  createdAt: true,
+  updatedAt: true,
+});
+
+export type SessionRequest = typeof sessionRequests.$inferSelect;
+export type InsertSessionRequest = z.infer<typeof insertSessionRequestSchema>;