v4 Semantics: loop rules and scope

New rules

break / continue

• break and continue are only valid inside loops.

for loop scope

• A for loop creates a new scope for its init.
• Variables declared in init are visible in the loop body and post.

logical operators

• && / || do not add new static rules.
• Both sides should still be analyzed (even though runtime short-circuits).

Implementation hints

• Track a loopDepth counter.
• When you enter a for or while, increment it.
• When you leave, decrement it.

Keep it straightforward and predictable.