feat(storage): repository traits, Postgres backend, and parity harness

.changeset/storage-lmdb-postgres.md

@@ -0,0 +1,2 @@
+---
+---

.github/workflows/checks.yml

@@ -223,6 +223,19 @@ jobs:
     runs-on: ubuntu-latest
     needs: changes
     if: needs.changes.outputs.rust == 'true'
+    services:
+      postgres:
+        image: postgres:16-alpine
+        env:
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_DB: postgres
+        ports:
+          - 5432:5432
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
     permissions:
       contents: read
     steps:
@@ -251,6 +264,14 @@ jobs:
           -D clippy::todo -D clippy::unimplemented -D clippy::panic
       - name: Tests
         run: cargo test --workspace --all-features
+      # The two database-backed storage targets create and migrate their own scratch
+      # databases; the Cucumber half of the harness stays in scripts/storage-parity.sh.
+      - name: Storage parity against Postgres
+        env:
+          PARITY_ADMIN_URL: postgres://postgres:postgres@localhost:5432/postgres
+        run: cargo test -p nostream-storage --test migrations --test parity -- --ignored --test-threads=1
+      - name: Storage builds without the Postgres driver
+        run: cargo check -p nostream-storage --no-default-features --all-targets
       - name: Release build
         run: cargo build --workspace --all-features --release
 

CLAUDE.md

@@ -36,6 +36,19 @@ cargo test --workspace --all-features
 cargo build --workspace --all-features --release
 ```
 
+CI additionally runs the two database-backed storage tests ("Storage parity against Postgres")
+against a `postgres:16-alpine` service, and they are `#[ignore]`d so a checkout without a database still passes
+`cargo test --workspace`:
+
+```
+cargo test -p nostream-storage --test migrations --test parity -- --ignored --test-threads=1
+```
+
+`PARITY_ADMIN_URL` names the administrative database (CI sets
+`postgres://postgres:postgres@localhost:5432/postgres`); the targets create, migrate and
+drop their own scratch databases. `scripts/storage-parity.sh` runs both plus the
+TypeScript Cucumber suite against the sqlx-migrated schema — the complete local oracle.
+
 - **`--workspace`, never a single crate.** A crate-local `cargo test -p` proves nothing
   about a workspace lint that another member trips.
 - **`--all-features` is not optional.** `nostreamd`'s `otlp` feature gates three