feat: validate CTE

CONTRIBUTING.md

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+# Contributing
+
+## Building from source
+
+```sh
+make all  # produces bin/sqlc-gen-go and bin/sqlc-gen-go.wasm
+```
+
+To use a local build:
+
+```yaml
+plugins:
+- name: golang
+  wasm:
+    url: file:///path/to/bin/sqlc-gen-go.wasm
+    sha256: ""  # optional since sqlc v1.24.0
+```
+
+## Testing
+
+```sh
+make test          # plugin internals + generated-code unit tests (no DB)
+make example-e2e   # end-to-end tests against a real PostgreSQL database
+```
+
+Run a single test:
+
+```sh
+go test ./internal/... -run TestName
+```
+
+Run fuzz tests:
+
+```sh
+go test ./internal/opts/... -fuzz FuzzOverride
+```
+
+## Benchmarks
+
+`emit_dynamic_filter` uses a pre-compiled query (parsed once at init, `Build()` per request) rather than parsing on every call. It is ~14–25× faster than one-shot parsing and matches or beats hand-written builders, with allocations down to 3–10 per call. Source and full numbers: [`example/bench/`](example/bench/).
+
+```sh
+cd example && go test ./bench -bench=. -benchmem -run='^$'
+```

MIGRATION.md

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+# Migrating from sqlc's built-in Go codegen
+
+Two changes are required:
+
+1. Add a top-level `plugins` entry pointing to the WASM plugin.
+2. Replace `gen.go` with `codegen`, referencing the plugin by name. Move all options into the `options` block; `out` moves up one level.
+
+**Before:**
+```yaml
+sql:
+- engine: postgresql
+  gen:
+    go:
+      package: db
+      out: db
+      emit_json_tags: true
+```
+
+**After:**
+```yaml
+plugins:
+- name: golang
+  wasm:
+    url: https://github.com/vtuanjs/sqlc-gen-go/releases/download/v3.0.1/sqlc-gen-go.wasm
+    sha256: f6a02c8cb363c56bb7a7de1d1012a65e800897696de9d28b938563af02e3ce81
+sql:
+- engine: postgresql
+  codegen:
+  - plugin: golang
+    out: db
+    options:
+      package: db
+      emit_json_tags: true
+```
+
+Global `overrides`/`go` move to `options`/`<plugin-name>`:
+
+```yaml
+options:
+  golang:
+    rename:
+      id: "Identifier"
+    overrides:
+    - db_type: "timestamptz"
+      nullable: true
+      engine: postgresql
+      go_type:
+        import: "gopkg.in/guregu/null.v4"
+        package: "null"
+        type: "Time"
+```