feat: Migrate documentation from Docusaurus to Mintlify (#211)

## Summary
- Replace Docusaurus docs site with Mintlify-powered documentation
- Sprinter Credit (V2) API reference with interactive playground and
response examples
- Stash Solver Credit (V1) API reference
- Quickstart guides: Card Programs (with authorization webhook) and
Agent Skills (health monitor, yield optimizer)
- Credit Engine, Policy Engine, and Risk Management documentation
- OpenAPI specs synced from upstream sprinter-api repo

## Mintlify Setup
After merging, update the Mintlify dashboard:
1. **Repository**: `sprintertech/sprinter-sdk`
2. **Branch**: `main`
3. **Subdirectory**: `docs`
4. **Custom domain**: `docs.sprinter.tech`

## Test plan
- [ ] Verify Mintlify build succeeds on this branch
- [ ] Check all navigation links work
- [ ] Confirm API playground loads for credit endpoints
- [ ] Review content accuracy with dev team

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: itsbobbyz <robert@chainsafe.io>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: 3 people

.github/workflows/ci.yml

@@ -29,49 +29,3 @@ jobs:
         run: "yarn run test:unit"
       - name: "Integrations Tests"
         run: "yarn run test:integrations"
-      - name: Set branch name for Cloudflare Pages
-        id: cf-branch
-        run: |
-          if [[ "${{ github.ref_name }}" == "master" ]]; then
-            echo "CF_BRANCH_NAME=preview" >> $GITHUB_ENV
-          else
-            echo "CF_BRANCH_NAME=${{ github.head_ref || github.ref_name }}" >> $GITHUB_ENV
-          fi
-      - name: Publish Docs to Cloudflare Pages
-        id: docs-publish
-        uses: cloudflare/wrangler-action@v3
-        with:
-          gitHubToken: ${{ secrets.GITHUB_TOKEN }}
-          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
-          accountId: 167153f505df751a355a8192b0656720
-          command: pages deploy ./docs/build --project-name=sprinter-docs --branch=${{ env.CF_BRANCH_NAME }}
-      - name: Publish POC to Cloudflare Pages
-        id: poc-publish
-        uses: cloudflare/wrangler-action@v3
-        with:
-          gitHubToken: ${{ secrets.GITHUB_TOKEN }}
-          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
-          accountId: 167153f505df751a355a8192b0656720
-          command: pages deploy ./web/.svelte-kit/cloudflare --project-name=sprinter-poc --branch=${{ env.CF_BRANCH_NAME }}
-      - name: Generate Deployment Summary
-        run: |
-          echo "# 🚀 Deployment Summary" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "| **Project**             | **Preview URL** |" >> $GITHUB_STEP_SUMMARY
-          echo "| ----------------------- | ---------------- |" >> $GITHUB_STEP_SUMMARY
-          echo "| **Docs**                | [View Docs -> ${{ steps.docs-publish.outputs.deployment-url }}](${{ steps.docs-publish.outputs.deployment-url }}) |" >> $GITHUB_STEP_SUMMARY
-          echo "| **POC**                 | [View POC -> ${{ steps.poc-publish.outputs.deployment-url }}](${{ steps.poc-publish.outputs.deployment-url }}) |" >> $GITHUB_STEP_SUMMARY
-      - name: Notify About Deployment
-        if: ${{ github.actor != 'dependabot[bot]' && github.ref_name != 'master' }}
-        uses: actions/github-script@v7
-        with:
-          script: |
-            const docsUrl = `**Docs:** [View Deployment -> ${{ steps.docs-publish.outputs.deployment-url }}](${{ steps.docs-publish.outputs.deployment-url }})`;
-            const pocUrl = `**POC:** [View Deployment -> ${{ steps.poc-publish.outputs.deployment-url }}](${{ steps.poc-publish.outputs.deployment-url }})`;
-            const message = `🚀 **Deployment Completed**\n\n${docsUrl}\n${pocUrl}`;
-            await github.rest.issues.createComment({
-              issue_number: context.issue.number,
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              body: message,
-            });

docs/.gitignore

@@ -0,0 +1,7 @@
+# Mintlify automatically ignores these files and directories:
+# .git, .github, .claude, .agents, .idea, node_modules,
+# README.md, LICENSE.md, CHANGELOG.md, CONTRIBUTING.md
+
+# Draft content
+drafts/
+*.draft.mdx

docs/.mintignore

@@ -0,0 +1,42 @@
+# Documentation project instructions
+
+## About this project
+
+- Sprinter API documentation site built on [Mintlify](https://mintlify.com)
+- Pages are MDX files with YAML frontmatter
+- Configuration lives in `docs.json`
+- Run `mint dev` to preview locally
+- Run `mint broken-links` to check links
+
+## Repos documented
+
+| Repo                            | Type                         | Spec                                                 |
+| ------------------------------- | ---------------------------- | ---------------------------------------------------- |
+| `sprintertech/miso-api`         | REST API (Go/Gin)            | OpenAPI 3.0 at `api-reference/miso/openapi.json`     |
+| `sprintertech/sprinter-api`     | REST API (Go/Gin)            | OpenAPI 3.0 at `api-reference/sprinter/openapi.json` |
+| `sprintertech/sprinter-signing` | MPC signing (Go/Gorilla Mux) | Manual MDX pages in `api-reference/signing/`         |
+| `sprintertech/stash-repayment`  | Background worker (Go)       | Architecture page in `architecture/`                 |
+
+## Terminology
+
+- "credit" — collateralized borrowing via CreditHub contracts
+- "solver" — entity that fills cross-chain intents
+- "earn vault" — yield-bearing wrapper (Morpho, Yo Protocol)
+- CAIP-2 format for chain IDs: `eip155:8453` (Base), `eip155:1` (Ethereum)
+- "MPC signing" — threshold signature scheme across multiple nodes
+
+## Style preferences
+
+- **LLM/agent-optimized**: prioritize code snippets, types, and structured tables over prose
+- Curl examples for every endpoint
+- Go type definitions from source code
+- JSON request/response examples
+- Minimal explanatory text — let code speak
+- Use tables for parameters, enums, and config
+- Use active voice and second person ("you")
+
+## Content boundaries
+
+- Do not document internal deployment/ops procedures
+- Do not document environment variables or secrets
+- Focus on external-facing API contracts only

docs/AGENTS.md

@@ -0,0 +1,34 @@
+> **Customize this file**: Tailor this template to your project by noting specific contribution types you're looking for, adding a Code of Conduct, or adjusting the writing guidelines to match your style.
+
+# Contribute to the documentation
+
+Thank you for your interest in contributing to our documentation! This guide will help you get started.
+
+## How to contribute
+
+### Option 1: Edit directly on GitHub
+
+1. Navigate to the page you want to edit
+2. Click the "Edit this file" button (the pencil icon)
+3. Make your changes and submit a pull request
+
+### Option 2: Local development
+
+1. Fork and clone this repository
+2. Install the Mintlify CLI: `npm i -g mint`
+3. Create a branch for your changes
+4. Make changes
+5. Navigate to the docs directory and run `mint dev`
+6. Preview your changes at `http://localhost:3000`
+7. Commit your changes and submit a pull request
+
+For more details on local development, see our [development guide](development.mdx).
+
+## Writing guidelines
+
+- **Use active voice**: "Run the command" not "The command should be run"
+- **Address the reader directly**: Use "you" instead of "the user"
+- **Keep sentences concise**: Aim for one idea per sentence
+- **Lead with the goal**: Start instructions with what the user wants to accomplish
+- **Use consistent terminology**: Don't alternate between synonyms for the same concept
+- **Include examples**: Show, don't just tell

docs/CHANGELOG.md

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023 Mintlify
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

docs/CONTRIBUTING.md

@@ -1,41 +1,26 @@
-# Website
+# Sprinter & Miso API Documentation
 
-This website is built using [Docusaurus](https://docusaurus.io/), a modern static website generator.
+> **Initial draft** — This is the first pass at API documentation for the Sprinter and Miso ecosystem. Content is auto-generated from OpenAPI specs and source code. Expect refinements, additional examples, and expanded coverage in future updates.
 
-### Installation
+## What's Documented
 
-```
-$ yarn
-```
-
-### Local Development
-
-```
-$ yarn start
-```
+| Service             | Source Repo                     | Type                                            |
+| ------------------- | ------------------------------- | ----------------------------------------------- |
+| **Miso API**        | `sprintertech/miso-api`         | REST API — user registration, cards, referrals  |
+| **Sprinter API**    | `sprintertech/sprinter-api`     | REST API — credit, liquidity, solver operations |
+| **Signing API**     | `sprintertech/sprinter-signing` | MPC threshold signing service                   |
+| **Stash Repayment** | `sprintertech/stash-repayment`  | Architecture overview (background worker)       |
 
-This command starts a local development server and opens up a browser window. Most changes are reflected live without having to restart the server.
+## Development
 
-### Build
+Requires Node 22 LTS (Node 25+ is not supported by Mintlify).
 
+```bash
+npx mintlify dev
 ```
-$ yarn build
-```
-
-This command generates static content into the `build` directory and can be served using any static contents hosting service.
 
-### Deployment
+Preview at `http://localhost:3000`.
 
-Using SSH:
-
-```
-$ USE_SSH=true yarn deploy
-```
-
-Not using SSH:
-
-```
-$ GIT_USER=<Your GitHub username> yarn deploy
-```
+## Publishing
 
-If you are using GitHub pages for hosting, this command is a convenient way to build the website and push to the `gh-pages` branch.
+Install the Mintlify GitHub app from your [dashboard](https://dashboard.mintlify.com/settings/organization/github-app) to auto-deploy on push to the default branch.