fix(evidence): preserve call coverage in function comparisons

Treat missing, partial, unknown, and unresolved call coverage as insufficient for call-set equality. Combine IDA caller/callee coverage without losing either explanation and recheck source coverage when verifying historical comparisons.

Scope generated function-comparison unknowns with optional typed comparison/dimension facts, preserving legacy IDs and revision digests when absent. Keep unrelated dimensions conclusive, explicit dependencies applicable, and ambiguous function identity unknown. A confirmed change for matched functions remains a failure even if calls are incomplete.

Validation: function/reconstruction/residual-unknown and bundle tests, recorded IDA protocol regression, public MCP comparison/verification, and advertised SDK JSON Schema checks. Real IDA provider execution was not verified.

Fixes #2222

src/contracts/functionComparisonExample.ts

@@ -50,6 +50,7 @@ const observe = (digit: string, text: string) =>
       result: dossier(text),
       confidence: "derived",
       authority: "shipped-artifact",
+      relationshipCoverage: { status: "complete" },
     },
   );