Stricter schema validation for extension and web TOMLs

[gonzaloriestra]

WHY are these changes introduced?

Related to https://shopify.slack.com/archives/C05E3BDFDRB/p1774273758576219

WHAT is this pull request doing?

• Reject unrecognized top-level keys in shopify.extension.toml (unified format) and shopify.web.toml by adding .strict() to UnifiedSchema and baseWebConfigurationSchema
• Previously, unknown keys were silently stripped by Zod's default behavior, causing misplaced configuration (e.g., putting [metaobjects] in extension TOML instead of app TOML) to be silently ignored
• Errors are collected via the existing AppErrors mechanism, consistent with how shopify.app.toml already rejects unsupported sections

How to test your changes?

Add an unknown field to shopify.extension.toml or shopify.web.toml and run deploy

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
• Existing analytics will cater for this addition
• PR includes analytics changes to measure impact

Checklist

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

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟢	Statements	82.42%	15152/18383
🟡	Branches	74.93%	7461/9957
🟢	Functions	81.43%	3805/4673
🟢	Lines	82.81%	14326/17299

Test suite run success

4004 tests passing in 1532 suites.

Report generated by 🧪jest coverage report action from 290f0c5

[github-actions]

We detected some changes at packages/*/src and there are no updates in the .changeset.
If the changes are user-facing, run pnpm changeset add to track your changes and include them in the next release CHANGELOG.

Caution

DO NOT create changesets for features which you do not wish to be included in the public changelog of the next CLI release.