feat: Parse struct name in complex field + ECC init macros as string

[jonathanpwang]

Cherry-picked from #1891 without the twisted Edwards macros.

The complex_init! and sw_init! macros are updated so that instead of parsing a Path, it parses a LitStr. This makes it so that the _init! macros do not require any path imports in the file where it is called, which greatly improves the developer experience.

The main files changed aside from test files and auto-generates openvm_init.rs files are:

• extensions/algebra/complex-macros/src/lib.rs
• extensions/ecc/sw-macros/src/lib.rs

In both macros, the change essentially boils down to changing:
(before)

        let items = input.parse_terminated(<Expr as Parse>::parse, Token![,])?;

to (after)

        let items = input.parse_terminated(<LitStr as Parse>::parse, Token![,])?;

and then associated type changes (mostly simplifications) in converting tokens to strings.

There is one additional change needed only for the sw_init! macro case. Previously the linked function

extern "C" fn #setup_extern_func()

defined by the sw_init! macro did use the path of the struct within the function implementation. After this PR, we avoid this import by moving that part of the logic into the fn set_up_once() function defined for the struct itself. This changed the function signature of the extern function to:

            extern "C" fn #setup_extern_func(uninit: *mut core::ffi::c_void, p1: *const u8, p2: *const u8)

Here is the diff of the code that was moved from the #setup_extern_func() into the set_up_once() function.

[codspeed-hq]

CodSpeed WallTime Performance Report

Merging #1945 will not alter performance

_{Comparing chore/init-macro-no-import (6342abf) with feat/new-execution (e67deab)}

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

Summary

✅ 27 untouched benchmarks

[github-actions]

group	app.proof_time_ms	app.cycles	app.cells_used	leaf.proof_time_ms	leaf.cycles	leaf.cells_used
verify_fibair	(-28 [-2.6%]) 1,067	322,660	18,749,844	-	-	-
fibonacci	(+16 [+0.8%]) 2,090	3,000,420	51,504,507	-	-	-
regex	(-39 [-0.6%]) 6,780	8,217,194	164,734,992	-	-	-
ecrecover	(+8 [+0.7%]) 1,136	(-324 [-0.1%]) 280,974	(-9031 [-0.1%]) 8,866,654	-	-	-
pairing	(+52 [+1.5%]) 3,560	(+39948 [+1.1%]) 3,765,878	(+707074 [+0.7%]) 98,834,293	-	-	-

Commit: 6342abf

Benchmark Workflow