Implement LocatorResolver helper generation and low-confidence warning surfacing

[kalen-releasedgroup]

Summary

Emit the helper logic that allows ranked locator resolution and useful runtime diagnostics.

Scope

• Generate the LocatorResolver helper abstraction.
• Support ranked candidate resolution, uniqueness validation, and optional scope handling.
• Surface low-confidence locator/assertion warnings in generation preview.

Requirement Links

• FR-GEN-004, FR-GEN-005
• Sections 9.4, 13.3

Dependencies

• Locator candidate persistence
• Generation pipeline

Exit Criteria

• Generated runtime helpers support ranked locator resolution.
• Preview surfaces expose low-confidence generation decisions.
• Generated assertions remain user-outcome oriented.