[Feature] Add configurable app URL path support for shopify.web.toml

[amcaplan]

WHY are these changes introduced?

Fixes #1181

This addresses the feature request to allow developers to configure custom app entry points in their shopify.web.toml configuration file. Currently, Shopify apps must use the root URL as their entry point, which limits flexibility for complex APIs where the Shopify app functionality is nested under a specific path (e.g., /api/shopify).

WHAT is this pull request doing?

This PR implements support for the app_url_path configuration parameter in shopify.web.toml files:

• Schema Extension: Added app_url_path as an optional string parameter to the web configuration schema with automatic path validation (ensures paths start with /)
• URL Generation: Updated generateApplicationURLs function to accept and use the configured app URL path when generating application URLs
• Dev Integration: Integrated the new configuration into the dev service workflow so that shopify app dev respects the custom app URL path
• Comprehensive Testing: Added tests to verify the functionality works correctly with and without the configuration

Example Usage:

# shopify.web.toml
roles = ["backend"]
app_url_path = "/api/shopify"
auth_callback_path = ["/api/shopify/install/callback", "/api/shopify/auth/callback"]

[commands]
dev = "npm run dev"

This generates URLs like https://myapp.com/api/shopify instead of https://myapp.com.

How to test your changes?

1. Create a new Shopify app or use an existing one
2. In the web directory, modify shopify.web.toml to include:

   app_url_path = "/custom/path"

3. Run shopify app dev
4. Verify that the application URL shown includes the custom path
5. Check that the app functionality works correctly at the custom URL path

Measuring impact

How do we know this change was effective? Please choose one:

• n/a - this doesn't need measurement, e.g. a linting rule or a bug-fix

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes

🤖 Generated with Claude Code

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟡	Statements	78.06% (+0.06% 🔼)	12540/16064
🟡	Branches	72.31% (+0.13% 🔼)	6086/8417
🟡	Functions	78.18% (-0.02% 🔻)	3286/4203
🟡	Lines	78.5% (+0.06% 🔼)	11867/15117

Show files with reduced coverage 🔻

St.❔	File	Statements	Branches	Functions	Lines
🔴	... / dev.ts	18.38% (-0.27% 🔻)	13.7%	23.81% (-1.19% 🔻)	19.05% (-0.15% 🔻)
🔴	... / app-management-client.ts	46.06% (-0.15% 🔻)	41.43%	43.27% (-0.42% 🔻)	44.9% (-0.15% 🔻)

Test suite run success

2893 tests passing in 1257 suites.

Report generated by 🧪jest coverage report action from 4af4d08

[nickwesselman]

/snapit

[github-actions]

🫰✨ Thanks @nickwesselman! Your snapshot has been published to npm.

Test the snapshot by installing your package globally:

pnpm i -g @shopify/cli@0.0.0-snapshot-20250605123019

Tip

If you get an ETARGET error, install it with NPM and the flag --@shopify:registry=https://registry.npmjs.org

Caution

After installing, validate the version by running just shopify in your terminal.
If the versions don't match, you might have multiple global instances installed.
Use which shopify to find out which one you are running and uninstall it.