feat: implement ai assistant for docs (#2189)

<!-- ELLIPSIS_HIDDEN -->


> [!IMPORTANT]
> Implements an AI assistant for documentation with a chatbot and search
interface, including backend query handling and frontend components.
> 
>   - **Backend**:
> - Adds `query.ts` and `rag.ts` in `sage-backend` for handling AI
queries and document retrieval.
>     - Implements middleware in `middleware.ts` for CORS handling.
> - Configures Next.js with `next.config.ts` and sets up `package.json`
dependencies.
> - Adds `generate-sitemap.ts` for sitemap generation and
`test-slugs.ts` for testing URL slugs.
>   - **Frontend**:
> - Implements `ChatBot.tsx` and `AlgoliaSearch.tsx` in `sage-client`
for AI chat and search interface.
> - Configures Webpack in `webpack.config.js` for building the chatbot.
> - Adds styling in `globals.css` and utility functions in `utils.ts`.
>     - Sets up `components.json` for component configuration.
>   - **Misc**:
>     - Removes `fern-check.yml` and `preview-docs.yml` workflows.
>     - Updates `publish-docs.yml` to include new build steps.
>     - Adds `postcss.config.mjs` for Tailwind CSS configuration.
> 
> <sup>This description was created by </sup>[<img alt="Ellipsis"
src="https://img.shields.io/badge/Ellipsis-blue?color=175173">](https://www.ellipsis.dev?ref=BoundaryML%2Fbaml&utm_source=github&utm_medium=referral)<sup>
for bc79e27. You can
[customize](https://app.ellipsis.dev/BoundaryML/settings/summaries) this
summary. It will automatically update as commits are pushed.</sup>


<!-- ELLIPSIS_HIDDEN -->

---------

Co-authored-by: Sam Lijin <[email protected]>

Author: egol

.github/workflows/fern-check.yml

@@ -1,21 +1,106 @@
 name: Publish Docs
 
+concurrency:
+  # No suffix specified - in reusable workflows we need a statically-defined suffix
+  # to prevent workflow_call workflows from triggering a concurrency deadlock
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 on:
+  pull_request:
   push:
     branches:
       - canary
 
 jobs:
-  run:
+  docs:
     runs-on: ubuntu-latest
+    permissions: write-all
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      - name: Setup Node.js and pnpm
+        uses: ./.github/actions/setup-node
+        with:
+          install-dependencies: false
+
       - name: Install Fern
         run: npm install -g fern-api
 
-      - name: Publish Docs
+      - name: Install dependencies and build custom.js
+        working-directory: ./typescript/apps/sage-client
+        run: pnpm install && pnpm run build
+
+      - name: Generate preview URL
+        id: generate-docs
         env:
           FERN_TOKEN: ${{ secrets.FERN_TOKEN }}
-        run: fern generate --docs
+        run: |
+          fern check --strict-broken-links
+          if [ "${{ github.event_name }}" = "push" ] && [ "${{ github.ref }}" = "refs/heads/canary" ]; then
+            OUTPUT=$(fern generate --docs 2>&1) || true
+          else
+            OUTPUT=$(fern generate --docs --preview 2>&1) || true
+          fi
+          echo "$OUTPUT"
+          URL=$(echo "$OUTPUT" | grep -oP 'Published docs to \K.*(?= \()')
+          echo "🌿 Preview your docs: $URL" | tee preview_url.txt
+
+      - name: Comment URL in PR
+        if: github.event_name == 'pull_request'
+        uses: thollander/[email protected]
+        with:
+          file-path: preview_url.txt
+
+  backend:
+    runs-on: ubuntu-latest
+    permissions: write-all
+    defaults:
+      run:
+        working-directory: ../sage-backend
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js and pnpm
+        uses: ./.github/actions/setup-node
+        with:
+          install-dependencies: false
+
+      - name: Install Fern
+        working-directory: .
+        run: npm install -g fern-api
+
+      - name: Pull sage-backend out of monorepo
+        working-directory: ./typescript
+        run: pnpm --filter=sage-backend deploy ../sage-backend
+
+      - name: Install dependencies and build
+        run: pnpm install && pnpm baml-cli generate
+
+      - name: Build Vercel project
+        env:
+          PINECONE_API_KEY: ${{ secrets.PINECONE_API_KEY }}
+        run: |
+          pnpm vercel pull --yes --token=${{ secrets.VERCEL_TOKEN_SAM }}
+          pnpm vercel build --token=${{ secrets.VERCEL_TOKEN_SAM }}
+
+      - name: Deploy preview backend
+        env:
+          VERCEL_ORG_ID: ${{ secrets.VERCEL_ORG_ID }}
+          VERCEL_PROJECT_ID: ${{ secrets.VERCEL_PROJECT_ID_SAGE_BACKEND }}
+        run: |
+          (
+            if [ "${{ github.event_name }}" = "push" ] && [ "${{ github.ref }}" = "refs/heads/canary" ]; then
+              pnpm vercel deploy --prod --prebuilt --token=${{ secrets.VERCEL_TOKEN_SAM }}
+            else
+              pnpm vercel deploy --prebuilt --token=${{ secrets.VERCEL_TOKEN_SAM }}
+            fi
+          ) | tee preview_url.txt
+
+      - name: Comment URL in PR
+        if: github.event_name == 'pull_request'
+        uses: thollander/[email protected]
+        with:
+          file-path: ../sage-backend/preview_url.txt

.github/workflows/preview-docs.yml

@@ -2,7 +2,7 @@ name: Release BAML CLI
 
 on:
   release:
-    types: [published, unpublished, created, edited, prereleased, drafted]
+    types: [published, unpublished, created, edited, prereleased]
 
 jobs:
   build-cli:

.github/workflows/publish-docs.yml

@@ -0,0 +1,2 @@
+custom.js
+custom.js.LICENSE.txt

.github/workflows/release-cli.yaml

@@ -323,6 +323,7 @@ body#fern-docs #fern-header .md\:h-\(--header-height-real\) {
 body#fern-docs .fern-sidebar-link[data-state="active"] span {
   color: var(--accent-primary) !important;
   font-weight: 600 !important;
+  font-family: var(--font-geist-sans);
 }
 
 body#fern-docs #fern-sidebar {