Frameless call to a leaf+thin+args-only function.
No CallFrame is pushed — just saves (fn_id, ip) in the dispatch loop,
sets bp to the args already on stack, and jumps to the target.
On RETURN, restores the caller’s state directly.
Format: fn_id:u16, argc:u8 (same as CALL_KNOWN).
LIST_GET + UNWRAP_OR fused: pop index, pop list, push value or default.
Format: const_idx:u16 (default value from constants pool).
Equivalent to: LIST_GET, LOAD_CONST idx, UNWRAP_OR.
Like MATCH_DISPATCH but every entry carries an inline result instead
of a jump offset. When an entry matches, the result is pushed directly
onto the stack and the match body is skipped entirely.
Tail-call self for thin frames: no arena finalization needed.
The compiler emits this instead of TAIL_CALL_SELF when the function
is known to be “thin” (no heap allocations within the frame).
Skips finalize_frame_locals_for_tail_call entirely — just copies
args in-place and resets ip.
Inline Option.withDefault: pop default, pop option → push inner or default.
Stack: [option, default] → [result]
If option is Some → push unwrapped inner value.
If option is None → push default.
Inline Result.withDefault: pop default, pop result → push inner or default.
Stack: [result, default] → [value]
If result is Ok → push unwrapped inner value.
If result is Err → push default.