feat(pipeline): emit CALLS edges for decorator applications

[map588]

Decorators previously only created DECORATES edges. References like @login_required were invisible to "find all references" queries which look for CALLS and USAGE edges. Now both sequential (resolve_decorator) and parallel (resolve_def_decorators) paths emit a CALLS edge alongside DECORATES.

Uses "{}" properties to avoid clobbering richer metadata from pass_calls when a function both has @decorator and calls decorator() directly.

[Copilot]

Pull request overview

This PR updates the indexing pipeline so decorator applications (e.g., @login_required) also emit CALLS edges (in addition to DECORATES) to make decorators visible to reference queries that traverse CALLS / USAGE relationships.

Changes:

• Emit a CALLS edge alongside DECORATES in the sequential semantic pass (resolve_decorator).
• Emit a CALLS edge alongside DECORATES in the parallel semantic resolver (resolve_def_decorators).
• Use "{}" edge properties to avoid overwriting richer CALLS metadata produced by pass_calls when an edge already exists.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/pipeline/pass_semantic.c	Adds a synthetic CALLS edge for each resolved decorator in the sequential semantic pass.
src/pipeline/pass_parallel.c	Adds a synthetic CALLS edge for each resolved decorator in the parallel semantic resolver path.

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[map588]

I noticed CBM was marking python functions as dead, because it had no callers, however the decorators were not taken into account. This marks them as "USAGE", so functions do not get falsely flagged as dead. @DeusData