fix: pin database-postgres driver to the golden tuple (pg 8.22.0, Kysely 0.29.4)

Review finding on PR #391: packages/database-postgres pinned pg@8.23.0 and
kysely@0.29.5, but the architecture doc's golden tuple (Technology-Stack
section 5.2 / section 7) pins pg@8.22.0 and Kysely@0.29.4. Reproducibility
requires the exact documented versions.

- packages/database-postgres/package.json: pg 8.23.0 -> 8.22.0,
  kysely 0.29.5 -> 0.29.4, @types/pg 8.23.1 -> 8.21.0 (no 8.22.x of
  @types/pg is published; 8.21.0 is the closest matching release, types
  for the immediately preceding pg minor)
- pnpm-lock.yaml: regenerated with pnpm 11.23.0 (Node 24); the resolved
  pg dependency tree is unchanged apart from the driver version itself
- tests/database-postgres-imports.test.mjs: exact-pin assertions updated
  to the corrected versions, with a comment noting the @types/pg choice

pnpm-lock.yaml

@@ -25,26 +25,26 @@ importers:
   packages/database-postgres:
     dependencies:
       kysely:
-        specifier: 0.29.5
-        version: 0.29.5
+        specifier: 0.29.4
+        version: 0.29.4
       pg:
-        specifier: 8.23.0
-        version: 8.23.0
+        specifier: 8.22.0
+        version: 8.22.0
     devDependencies:
       '@types/pg':
-        specifier: 8.23.1
-        version: 8.23.1
+        specifier: 8.21.0
+        version: 8.21.0
 
 packages:
 
   '@types/node@24.13.3':
     resolution: {integrity: sha512-Dh8vAsV36ig5wa9OX4pXvMc9D3Veibfw2wix0CUwYODLD8nkj9UsLjASr49nPg+2eKzxhBV+v7L8pXvT4e639Q==}
 
-  '@types/pg@8.23.1':
-    resolution: {integrity: sha512-fKVHpikPdg4GKks3JuLEhvwSyvwzF23hnabPy6DD8ljVbC7+6J5dQzdv4arV6jqq57djnMgs1HKBxX4P8aBI3A==}
+  '@types/pg@8.21.0':
+    resolution: {integrity: sha512-AYdtudzabjLZgVgRZmAnU8bAnVUXzuJX2IYHeSIiIHm68olD+LgQYCGWdtcNYnP0uq9c4S4NibVG3Ni7VbKW7Q==}
 
-  kysely@0.29.5:
-    resolution: {integrity: sha512-ooa+eSbBNPTo3MycPEuW5jdrxQdQwdtB3LC3h43FiXQbIry5tR0C5lDG7eealK0E4D7XjrnOP5DIUg/LyjRMYQ==}
+  kysely@0.29.4:
+    resolution: {integrity: sha512-y5mVgQNkMbs1eK9Xyc0pmNdabN2wHhRYY/5r4W5HrUT1rYCEPeVNSj1RUJeSDKT3U0p+mXCvLgkrFuIafYI6BA==}
     engines: {node: '>=22.0.0'}
 
   pg-cloudflare@1.4.0:
@@ -69,8 +69,8 @@ packages:
     resolution: {integrity: sha512-qTAAlrEsl8s4OiEQY69wDvcMIdQN6wdz5ojQiOy6YRMuynxenON0O5oCpJI6lshc6scgAY8qvJ2On/p+CXY0GA==}
     engines: {node: '>=4'}
 
-  pg@8.23.0:
-    resolution: {integrity: sha512-Ip2EQCngowJLGOfCwkFhPXU7/ljlhn6Rxlmy4XYfL2Y+vyRM59+8uR2xqRWKdYmbXmxCFOAmKxBuSUCdF34qLg==}
+  pg@8.22.0:
+    resolution: {integrity: sha512-8wih1vVIBMxoUM2oB4soJsD9tDnDpLv4OXBJ+EJzFsvycD+lfyIreC2gGHq78f8jbLLt+bvlPTFdFZfJkOuzAA==}
     engines: {node: '>= 16.0.0'}
     peerDependencies:
       pg-native: '>=3.0.1'
@@ -119,13 +119,13 @@ snapshots:
     dependencies:
       undici-types: 7.18.2
 
-  '@types/pg@8.23.1':
+  '@types/pg@8.21.0':
     dependencies:
       '@types/node': 24.13.3
       pg-protocol: 1.16.0
       pg-types: 2.2.0
 
-  kysely@0.29.5: {}
+  kysely@0.29.4: {}
 
   pg-cloudflare@1.4.0:
     optional: true
@@ -134,9 +134,9 @@ snapshots:
 
   pg-int8@1.0.1: {}
 
-  pg-pool@3.14.0(pg@8.23.0):
+  pg-pool@3.14.0(pg@8.22.0):
     dependencies:
-      pg: 8.23.0
+      pg: 8.22.0
 
   pg-protocol@1.16.0: {}
 
@@ -148,10 +148,10 @@ snapshots:
       postgres-date: 1.0.7
       postgres-interval: 1.2.0
 
-  pg@8.23.0:
+  pg@8.22.0:
     dependencies:
       pg-connection-string: 2.14.0
-      pg-pool: 3.14.0(pg@8.23.0)
+      pg-pool: 3.14.0(pg@8.22.0)
       pg-protocol: 1.16.0
       pg-types: 2.2.0
       pgpass: 1.0.5