run: wrapper orphans the binary on SIGTERM, agent config keys fold silently, no token budget #1656

Problem

Three gaps make a headless altimate-code run hard to bound and stop from a driver script:

• Killing the wrapper orphans the binary. bin/altimate-code runs the compiled binary with spawnSync, which installs no signal handling. kill <wrapper pid> (SIGTERM from a harness, timeout, a CI cancel) ends the Node wrapper and leaves the binary running with no parent. Observed: a run kept working and spending tokens after its driver had killed the wrapper at its budget.
• Unknown agent config keys are folded into options without a word. ConfigAgentV1.normalize copies every top-level key it does not interpret into options. A typo such as budget: 30 for steps: 30 is accepted, does nothing, and leaves no trace in the log.
• run has no token budget. --max-turns and --time-budget bound turns and wall-clock time, but nothing bounds billed tokens, and task subagent sessions spend outside the root session's turn count.

Expected

• Termination signals sent to the wrapper reach the binary; exit codes stay as they are.
• A folded agent key is at least reported.
• An optional --max-tokens <n> stops the run (root and task sessions together) and finalizes it the same way --time-budget does. Without the flag nothing changes.