Why must a hedge of a highly probable FORECASTED transaction be a cash flow hedge rather than a fair value hedge — what is structurally missing?

A company holds a forward exchange contract that is NOT designated as a hedge (pure speculation). The forward's fair value swings between reporting dates. Where do those gains and losses go, and what makes this different from a cash flow hedge?

In a cash flow hedge, the effective portion of the hedging instrument's gain or loss sits in OCI. What single event triggers its reclassification into net income, and why is the timing the whole point?

A colleague says of a foreign-currency receivable outstanding across a reporting date: "we recorded it at the spot rate when it arose, so no entry until we collect." What is wrong, and what is the financial-statement effect?

A client holds Bitcoin and wants to apply IAS 21, booking exchange gains/losses on it like a foreign-currency balance. Why does IAS 21 NOT apply, and what is the consequence of that boundary?

In a fair value hedge, where does the gain/loss on the HEDGED ITEM (for the hedged risk) go, and why does that force the hedging instrument's gain/loss to the same place?

You hedge a recognized foreign-currency receivable with a forward contract. Which hedge type fits — fair value or cash flow — and what property of the receivable decides it?