Release v0.2.81

[AntoineToussaint]

Objective

Release Core v0.2.81 from current main.

Included

• Scope semantic declaration identities to their enclosing callable
• Exclude function-local data declarations from the durable declaration graph
• Preserve qualified identities for nested callables
• Publish semantic analyzer provenance as codefly.semantic-index/v2

Definition of done

• Version metadata is 0.2.81
• Full CI passes
• Annotated v0.2.81 tag is pushed from the exact merged main commit
• GitHub release workflow succeeds