Lunatik v4.2

@sneaky-potato

Lunatik 4.2

luaskb: wraps struct sk_buff for direct packet manipulation from Lua — skb:data([layer]), skb:forward(), skb:copy(), skb:resize(n), skb:ifindex(), skb:vlan(), with IPv6 checksum support; skb:copy() guards against FRAGLIST GSO skbs
darken + lighten: AES-256-CTR encrypted Lua script support — darken (C module) decrypts and executes scripts in-kernel; lighten (Lua) provides the high-level interface

lunatik.runtime(script, context): the sleep boolean parameter is now a context string — "softirq" replaces false for non-sleepable runtimes; CLI: lunatik run <script> softirq
data.new(size, mode): new optional mode parameter ("single", "shared") controls object sharing semantics
data:checksum(): new method — raw IP checksum over the data buffer; luadata_reset no longer takes an offset parameter
socket.unix: rewritten from a dynamic factory pattern to explicit OOP-style classes (unix.stream, unix.dgram) with full method set; tests added
lunatik_opt_t (C API): new bitmask type replaces the bool sleep and bool shared parameters throughout the API — lunatik_runtime(), lunatik_newobject(), lunatik_createobject(), and lunatik_class_t all take lunatik_opt_t now; flags: LUNATIK_OPT_SOFTIRQ (non-sleepable), LUNATIK_OPT_MONITOR (spinlock serialization), LUNATIK_OPT_SINGLE (no monitor overhead for per-object instances), LUNATIK_OPT_EXTERNAL (externally-owned pointer)
luarcu (C API): entries now store lunatik_value_t (tagged union) instead of raw object pointers — supports nil, boolean, integer, and Lunatik objects as values

Full REPL rewrite: multi-line input, readline support, expression auto-detection, multiple return values
New lunatik test [suite] command
Argument validation for run/spawn/stop
Globals and runner state now initialized correctly when modules are pre-loaded (e.g., via modprobe at boot) without calling lunatik load first

Fix GC finalizers running under spinlock in lunatik_monitor (scheduling-while-atomic crash)
Fix opaque error messages in lunatik_monitor — errors now include method name and Lua traceback
Fix module refcount leak on runtime error path
Fix shouldstop() crash when called outside kthread context
Fix thread.run error during module load

KTAP shell framework introduced for all test suites
New regression tests: GC-under-spinlock, rcu_shared, resume_shared, shouldstop, spawn-during-module-load, opt_guards, opt_skb_single
New socket/unix test suites (STREAM and DGRAM)

Thank you to everyone who contributed to this release:

@sneaky-potato — opaque error messages in lunatik_monitor, non-shared objects in shared class, remove Lua traceback from lunatik_fixerror, README fix
@carloslack — data:checksum() (raw IP checksum), skb:vlan(), removed unneeded includes
@Suryansh-Dey — fix sockaddr version guard (first contribution! 🎉)

Full Changelog: v4.1.1...v4.2