```python
"""Close out a stockroom count sheet after a day's receive and issue moves."""

import re


def closing_sheet(opening: str, moves: str) -> str:
    if not isinstance(opening, str) or not isinstance(moves, str):
        raise ValueError("closing_sheet expects two strings")

    def parse_sheet(text):
        held = {}
        if text == "":
            return held
        for part in text.split(";"):
            name, colon, count = part.partition(":")
            if colon == "":
                raise ValueError(f"sheet entry has no colon: {part}")
            if re.fullmatch(r"[a-z]+", name) is None:
                raise ValueError(f"bad item name: {part}")
            if re.fullmatch(r"0|[1-9]\d*", count) is None:
                raise ValueError(f"bad count: {part}")
            if name in held:
                raise ValueError(f"duplicate sheet entry: {name}")
            held[name] = int(count)
        return held

    def apply_moves(held, moves):
        for part in moves.split(";"):
            if not part:
                continue
            parts = part.split("+")  # Receive move
            if len(parts) != 2:
                raise ValueError(f"bad move: {part}")
            name, qty_str = parts
            qty = int(qty_str)
            if name not in held or held[name] < qty:
                raise ValueError(f"issue of item '{name}': cannot receive {qty}, only {held.get(name, 0)} available")
            held[name] += qty

        for part in moves.split(";"):
            if not part:
                continue
            parts = part.split("-")  # Issue move
            if len(parts) != 2:
                raise ValueError(f"bad move: {part}")
            name, qty_str = parts
            qty = int(qty_str)
            if name not in held or held[name] < qty:
                raise ValueError(f"issue of item '{name}': cannot issue {qty}, only {held.get(name, 0)} available")
            held[name] -= qty

    held = parse_sheet(opening)
    apply_moves(held, moves)

    entries = []
    for name in sorted(held):
        if held[name] > 0:
            entries.append(f"{name}:{held[name]}")

    return ";".join(entries) if entries else ""
```