test: add redemption-window overlap rejection test (Closes #552)

[Chummy-debug]

Description

Re-adds set_redemption_window / get_redemption_window (accidentally removed in commit 6939ad3) with overlap protection: setting a second window that collides with an existing unconsumed window is rejected with RedemptionWindowOverlap.

Changes

• src/lib.rs: Added RedemptionWindowOverlap = 77 error variant; re-added set_redemption_window and get_redemption_window in the #[contractimpl] block with overlap checking; restored missing DataKey2 variants referenced by active code
• src/test_redemption.rs: Added set_redemption_window_rejects_overlap (left/right/containment/surround) and set_redemption_window_allows_contiguous_non_overlapping (end==start boundary)
• src/structured_error_tests.rs: Registered the new variant for discriminant uniqueness
• tools/storage_layout_schema.rs: Synced registry with source enums

Overlap definition

Two windows [a_start, a_end) and [b_start, b_end) overlap when a_start < b_end && b_start < a_end. Adjacent windows (end == start) are allowed.

Build note

upstream/master has pre-existing compilation errors unrelated to this PR (appear on a clean checkout before these changes).

[drips-wave]

Hey @Chummy-debug! 👋 It looks like this PR isn't linked to any issue.

If this PR is for one of the issues assigned to you as part of a Wave, please link it to ensure your contribution is tracked properly. You can do this by adding a keyword to the PR description (e.g., Closes #123), or by clicking a button below:

Issue	Title
#552	Add redemption-window overlap test asserting rejection when two windows collide	Link to this issue

ℹ️ Learn more about linking PRs to issues