Summary

• Add expression compiler (type-level and runtime) for lens expressions
• Support property access (.name), bracket notation (['key']), tuple ([N])
• Support type-level-only syntax: array ([]), indexed (:), awaited (#), returned (>), parameters (())
• Add Lens.get (uncurried), Lens.getWith (curried), Lens.getOn (inverse curried)
• Remove Obj.getWith, Obj.getOn, Obj.path in favor of Lens equivalents
• Migrate str/template.ts to use Lens.getOn

Examples

// Property access
Lens.get('.user.address.city', data)  // typed result

// Curried for pipelines
users.map(Lens.getWith('.name'))

// Inverse curried for multiple extractions
const fromUser = Lens.getOn(user)
fromUser('.name')
fromUser('.address.city')

// Type-level only
type T = Lens.Get<'.items[]', { items: number[] }>  // number
type T = Lens.Get<'.data:', { data: Record<string, number> }>  // number

BREAKING CHANGE

Removed Obj.getWith, Obj.getOn and Obj.path exports - use Lens.get/Lens.getWith/Lens.getOn instead.

Test plan

• Type checking passes
• All 2956 tests pass
• Lens module tests cover all expression syntax