Generate Zod schemas from codersdk via guts

Hand-maintained Zod schemas drifted from the Go SDK
and caused CODAGT-507. This replaces them with codegen.

scripts/typegen/ parses codersdk with guts, walks the
intermediate AST, and emits Zod v4 schemas to
src/codersdk.gen.ts. A daily CI cron checks for drift
against coder/coder tip.

ChatMessagePart is mapped to z.unknown() because guts
flattens the discriminated union into a single object.
CreateChatMessageResponse is hand-written since the
action only reads the queued field.

Author: mafredri

.gitattributes

@@ -1 +1,2 @@
 dist/index.js linguist-generated -diff -whitespace
+src/codersdk.gen.ts linguist-generated

.github/workflows/typegen-drift.yaml

@@ -0,0 +1,50 @@
+name: Typegen Drift Check
+
+on:
+  schedule:
+    # Run daily at 06:00 UTC.
+    - cron: "0 6 * * *"
+  workflow_dispatch:
+
+jobs:
+  typegen-drift:
+    name: Check for codersdk schema drift
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v6
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: scripts/typegen/go.mod
+
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: 1.3.14
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Update codersdk to latest
+        working-directory: scripts/typegen
+        run: go get github.com/coder/coder/v2@main && go mod tidy
+
+      - name: Regenerate schemas
+        run: make gen
+
+      - name: Check for drift
+        run: |
+          if ! git diff --quiet -- src/codersdk.gen.ts; then
+            echo "::error::codersdk schema drift detected. The generated schemas are out of date with the latest coder/coder."
+            echo ""
+            echo "Diff:"
+            git diff -- src/codersdk.gen.ts
+            echo ""
+            echo "To fix: run 'cd scripts/typegen && go get github.com/coder/coder/v2@main && go mod tidy && cd ../.. && make gen' and commit the result."
+            exit 1
+          fi
+          echo "No drift detected."

Makefile

@@ -1,8 +1,15 @@
-.PHONY: fmt fmt-check lint test clean deps all
+.PHONY: fmt fmt-check lint test clean deps all gen
 
-TS_FILES := $(shell find src -name "*.ts" -type f ! -name "*.test.ts")
+TS_FILES := $(shell find src -name "*.ts" -type f ! -name "*.test.ts" ! -name "*.gen.ts")
 
-all: build fmt lint test
+all: gen build fmt lint test
+
+gen: src/codersdk.gen.ts
+
+src/codersdk.gen.ts: scripts/typegen/main.go scripts/typegen/zod.go scripts/typegen/go.mod
+	@cd scripts/typegen && go run . > ../../src/codersdk.gen.ts.tmp
+	@mv src/codersdk.gen.ts.tmp src/codersdk.gen.ts
+	@bun run format -- src/codersdk.gen.ts || true
 
 fmt:
 	bun run format
@@ -14,7 +21,7 @@ lint:
 	bun run lint
 	bun run typecheck
 
-dist/index.js: $(TS_FILES) package.json bun.lock node_modules
+dist/index.js: $(TS_FILES) src/codersdk.gen.ts package.json bun.lock node_modules
 	bun run build
 
 build: dist/index.js