M0: foundation — monorepo, PostGIS schema, deck query, app shell

Greenfield scaffold for Linkder, a swipe-to-hire marketplace for local
professional services.

- pnpm/turbo monorepo: apps/web, packages/{shared,db}
- Postgres 16 + PostGIS via docker compose (ports 5442/6389 to avoid
  clashing with other local stacks)
- Drizzle schema, 23 tables, geography(Point,4326) with GiST indexes
- Domain core in packages/shared: integer-cent money, status transition
  graphs, deck ranking weights, cancellation policy — 46 unit tests
- Deck query: filtering in Postgres on the GiST index, ranking in JS so
  the weights stay tunable — 18 integration tests against a seeded DB
- Deterministic seed placing pros at known distances, including three
  that must NOT appear on a deck (out of radius, unverified, away)
- Next.js 15 app shell with a working swipe deck
- CI: typecheck, lint, test, build against live postgres+redis

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

packages/db/src/schema/messaging.ts

@@ -0,0 +1,32 @@
+import { relations, sql } from 'drizzle-orm';
+import { index, pgTable, text, timestamp, uuid } from 'drizzle-orm/pg-core';
+import { users } from './auth';
+import { matches } from './matching';
+
+export const messages = pgTable(
+  'messages',
+  {
+    id: uuid('id').primaryKey().defaultRandom(),
+    matchId: uuid('match_id')
+      .notNull()
+      .references(() => matches.id, { onDelete: 'cascade' }),
+    senderId: uuid('sender_id')
+      .notNull()
+      .references(() => users.id, { onDelete: 'cascade' }),
+    body: text('body').notNull(),
+    attachments: text('attachments').array().notNull().default(sql`'{}'::text[]`),
+    readAt: timestamp('read_at', { withTimezone: true }),
+    createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+  },
+  (t) => [
+    // Chat history is always "this match, newest last".
+    index('messages_match_idx').on(t.matchId, t.createdAt),
+    // Unread badge count.
+    index('messages_unread_idx').on(t.matchId, t.senderId).where(sql`${t.readAt} IS NULL`),
+  ],
+);
+
+export const messagesRelations = relations(messages, ({ one }) => ({
+  match: one(matches, { fields: [messages.matchId], references: [matches.id] }),
+  sender: one(users, { fields: [messages.senderId], references: [users.id] }),
+}));