Fix the Edge runtime sandbox timer lifecycle so fire-and-forget one-shot timeouts are no longer retained after their callbacks finish. This must also hold when a callback throws and across repeated rounds in a long-lived module context, preventing tracked timer resources from growing monotonically. Preserve the sandbox's existing web-compatible callback `this` value and extra-argument behavior, as well as its workaround for primitive Node timer handles. Explicitly clearing a pending timeout must still cancel it and release its tracking. Repeating intervals must remain tracked after firing and be cleared only by an explicit clear or sandbox teardown.