Usage and "limited until" reach the meter from the runner, not one CLI's event format #12123

Done looks like:

• The runner seam reports spend as {tokens in, tokens out, cost?} and a limit as {limitedUntil: time}
• src/crew/limits.ts and the usage meter read only that shape; parsing the CLI's rate-limit events lives in claude.ts
• A test feeds a fake runner's limit and the crew pauses until that time

Files: src/crew/agent_runner.ts, src/crew/claude.ts, src/crew/limits.ts, test/crew-limits.test.ts

Part of the owner's ask #12068 (AI agnostic). Keep this pull to the files named; earlier tries went red by spreading into src/flow, src/core/events and src/boards. A new process start must be listed in test/spawn-sites.test.ts (and test/spawn-pipes.test.ts) with its reason. The branch mason/12068-the-forge-is-ai-agnostic-you-connect-you (f580581a93e3) holds earlier work to borrow from, not to merge whole.