fix: drop mustache dependency

[ferhatelmas]

What kind of change does this PR introduce?

Refactor

What is the current behavior?

Mustache is used for RLS tests but we don't use any partials, blocks, etc. Instead simple interpolation.

What is the new behavior?

Use string replace with one liner to drop the dependency.

Additional context

The less dependency we need, the better it is for maintenance even if dev dependency.

[Copilot]

Pull request overview

This PR removes the mustache dependency from the RLS test suite by replacing Mustache rendering with a small, purpose-built string interpolation helper.

Changes:

• Replaced Mustache.render(...) usage in src/test/rls.test.ts with a local renderRlsTemplate(...) implementation.
• Removed mustache and @types/mustache from package.json and pruned them from package-lock.json.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated no comments.

File	Description
src/test/rls.test.ts	Introduces a lightweight {{var}} interpolator for test YAML templating and replaces Mustache usage.
package.json	Drops mustache and @types/mustache dev dependencies.
package-lock.json	Removes resolved entries for mustache and @types/mustache.

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[TylerHillery]

We are going to have no dependencies left by this rate you're removing them