fix: separate schema constructor drift contexts

[ApexWorm]

Problem

The Python schema_drift detector globally clustered declarative schema dictionaries with runtime payload dictionaries. This can flag intentionally optional contract keys as drift, and a normal subsequent scan preserves the invalidated detector output as strict auto_resolved debt.

Fix

• Keep dictionaries passed directly to named *Schema constructors in their own comparison scope.
• Preserve genuine drift detection within the same schema-constructor family and within generic runtime payloads.
• Emit scanner-proven, exact-fingerprint semantic corrections only on a confirmed full scan.
• Reclassify only those historic items as false_positive, with attestation, and remove them from the uncommitted ledger without using a skip or weakening ordinary auto_resolved strict semantics.

Verification

• Focused detector, state, plan, scoring, and scan-plan reconciliation suites passed.
• Exact source probe verified scoped suppression and the historical-item lifecycle.
• Full suite: 5,818 passed, 4 skipped; two pre-existing review-prompt tests fail because generated prompts no longer include Previously flagged issues.