Adds support for running EVAL with different scripting engines

[rjd15372]

In this PR we re-implement the EVAL commands (EVAL, EVALSHA, SCRIPT LOAD, etc...) to use the scripting engine infrastructure introduced in 6adef8e. This allows EVAL to run scripts using different scripting engines.

The Lua scripting engine implementation code was moved into its own subdirectory src/lua.

This new implementation generalizes the module API for implementing scripting engines to work with both FUNCTION and EVAL commands.

Module API changes include:

• Rename of callback ValkeyModuleScriptingEngineCreateFunctionsLibraryFunc to ValkeyModuleScriptingEngineCompileCodeFunc.
• Addition of a new enum enum ValkeyModuleScriptingEngineSubsystemType to specify the scripting engine subsystem (EVAL, or FUNCTION, or both).
• In most callbacks was added a new parameter with the type ValkeyModuleScriptingEngineSubsystemType.
• New callback specific for EVAL ValkeyModuleScriptingEngineResetEvalEnvFunc.
• New API function ValkeyModuleScriptingEngineExecutionState (*ValkeyModule_GetFunctionExecutionState)(ValkeyModuleScriptingEngineServerRuntimeCtx *server_ctx) that is used by scripting engines to query the server about the execution state of the script that is running.

Fixes #1261
Follow-up of #1277

[codecov]

Codecov Report

Attention: Patch coverage is 62.76978% with 414 lines in your changes missing coverage. Please review.

Project coverage is 71.03%. Comparing base (921ba19) to head (b8e97eb).
Report is 1 commits behind head on unstable.

Files with missing lines	Patch %	Lines
src/lua/debug_lua.c	39.27%	354 Missing ⚠️
src/lua/engine_lua.c	88.48%	19 Missing ⚠️
src/eval.c	91.83%	16 Missing ⚠️
src/lua/script_lua.c	70.00%	9 Missing ⚠️
src/server.c	25.00%	9 Missing ⚠️
src/module.c	20.00%	4 Missing ⚠️
src/scripting_engine.c	92.59%	2 Missing ⚠️
src/lua/function_lua.c	97.67%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #1497      +/-   ##
============================================
+ Coverage     70.98%   71.03%   +0.05%     
============================================
  Files           120      123       +3     
  Lines         65095    65298     +203     
============================================
+ Hits          46210    46387     +177     
- Misses        18885    18911      +26     

Files with missing lines	Coverage Δ
src/defrag.c	91.98% <ø> (+2.35%)	⬆️
src/functions.c	94.31% <100.00%> (+2.30%)	⬆️
src/lazyfree.c	86.11% <100.00%> (ø)
src/server.h	100.00% <ø> (ø)
src/lua/function_lua.c	98.69% <97.67%> (ø)
src/scripting_engine.c	76.85% <92.59%> (ø)
src/module.c	9.61% <20.00%> (+<0.01%)	⬆️
src/lua/script_lua.c	89.74% <70.00%> (ø)
src/server.c	87.47% <25.00%> (-0.20%)	⬇️
src/eval.c	89.13% <91.83%> (+32.06%)	⬆️
... and 2 more

... and 9 files with indirect coverage changes

[rjd15372]

@zuiderkwast this is ready for review.

[zuiderkwast]

It's a huge change.

The module API changes look good to me.

It's impossible to proof-read the logic but I guess we have pretty good test coverage. Breaking up eval.c into smaller units is good idea, just hard to review. Can you summarize which code was just moved unchanged and which code was written, so it's possible to tell what to review carefully and what not?

[zuiderkwast]

We should have some copyright/license comment at the top. I believe 3 lines are enough:

# Copyright xxxxxxxxxxxx
# All rights reserved.
# SPDX-License-Identifier: BSD-3-Clause

We use Copyright 2025- Valkey contributors for new files, but for moved code we should probably keep the old names and years too.

[zuiderkwast]

module.h is included twice here