fix(db): squash migrations to single baseline (cold-migrate was broken)

0000_easy_slipstream already created lists/list_shares/list_items and the
calendars unique constraint, but 0001_lists_schema re-created those tables and
0001_calendars_user_url_unique was an orphan (not in _journal) — so a cold
`drizzle-kit migrate` against an empty DB failed with ERROR 1050 'Table lists
already exists'. Dev only survived because its DB was built incrementally; CI
is the first cold migrate and exposed it.

Regenerated a single 0000_baseline.sql from schema.ts. Verified on a fresh
mariadb:11: migrate succeeds, schema is structurally identical to the running
dev DB, `drizzle-kit generate` reports no drift, and all 238 API tests pass.
Local dev DBs must be rebuilt (drop + db:migrate); no prod exists.

apps/api/src/db/migrations/meta/_journal.json

@@ -5,36 +5,8 @@
     {
       "idx": 0,
       "version": "5",
-      "when": 1781020239657,
-      "tag": "0000_easy_slipstream",
-      "breakpoints": true
-    },
-    {
-      "idx": 1,
-      "version": "5",
-      "when": 1781020500000,
-      "tag": "0001_lists_schema",
-      "breakpoints": true
-    },
-    {
-      "idx": 2,
-      "version": "5",
-      "when": 1781029240528,
-      "tag": "0002_yielding_mattie_franklin",
-      "breakpoints": true
-    },
-    {
-      "idx": 3,
-      "version": "5",
-      "when": 1781052360194,
-      "tag": "0003_same_xavin",
-      "breakpoints": true
-    },
-    {
-      "idx": 4,
-      "version": "5",
-      "when": 1781058250993,
-      "tag": "0004_mature_maximus",
+      "when": 1781202409890,
+      "tag": "0000_baseline",
       "breakpoints": true
     }
   ]