fix: resolve LTO type mismatch for R_igraph_eigen_matrix, R_igraph_eigen_matrix_symmetric, and R_igraph_get_shortest_path_astar

[Copilot]

Summary

Fixes the following LTO type mismatch warnings reported during package installation:

cpp11.cpp:173:13: warning: type of 'R_igraph_eigen_matrix_symmetric' does not match original declaration [-Wlto-type-mismatch]
cpp11.cpp:172:13: warning: type of 'R_igraph_eigen_matrix' does not match original declaration [-Wlto-type-mismatch]
cpp11.cpp:215:13: warning: type of 'R_igraph_get_shortest_path_astar' does not match original declaration [-Wlto-type-mismatch]

Root Cause

The ARPACKFUNC and ASTAR_HEURISTIC_FUNC types in tools/stimulus/types-RC.yaml had HEADER: {} (an empty dict, which is falsy in Python), causing Stimulus to omit these parameters from the C function signatures in the generated rinterface.c. However:

• The R wrappers in aaa-auto.R correctly included these as .Call() arguments (because types-RR.yaml has no HEADER override for these types, so Stimulus defaults to using the parameter name)
• cpp11.cpp is auto-generated to match the R call argument counts

This created a mismatch: cpp11.cpp declared/registered R_igraph_eigen_matrix and R_igraph_eigen_matrix_symmetric with 7 parameters and R_igraph_get_shortest_path_astar with 6, but the corresponding C functions in rinterface.c had 6 and 5 parameters respectively.

Fix

Changed HEADER: {} to HEADER: '%I%' for ARPACKFUNC and ASTAR_HEURISTIC_FUNC in tools/stimulus/types-RC.yaml, then regenerated src/rinterface.c. The C functions now accept the SEXP parameters in their signatures (fixing the LTO mismatch) while still passing 0 (NULL) to the underlying igraph C calls (since CALL: '0' is unchanged — the R-level callback values are received but not forwarded to C).

Testing

• Package compiles without LTO type mismatch warnings
• All 7994 tests pass