feat(hir): support interface modports

[hongjr03]

Summary

This change adds first-class HIR support for SystemVerilog interface modports and virtual interface typing.

• lowers modport declarations into module-owned HIR definitions with source ranges
• exposes DefLoc::Modport and DefKind::Modport through scope, definition lookup, display, and document symbols
• types interface definitions, interface instances, and modport selections as virtual interfaces
• lets interface instance member paths such as u_if.host and u_if.clk resolve through the interface scope
• adds IDE regression coverage for interface instance and modport navigation and hover
• centralizes the instantiable module-like definition predicate for module, interface, and program definitions

Validation

• cargo build
• cargo fmt --all -- --check
• cargo xtask check-config-artifacts
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test -p hir
• cargo test -p ide
• cargo test --workspace
• git diff --check master..HEAD