[gelzinn]

Description

With auto-switch on, launching a seat that is already at its usage limit with args that resume a conversation (seats run claude:b --resume <id>) moved to the next seat but kept the same args, so the CLI there looked for a conversation that seat doesn't have. Only the mid-session switch copied the transcript. This is exactly the command the herdr plugin from #18 reports for restored panes, and what seats move's "open now" runs.

• A new sessions.resumedId(args) reads the session id back from each tool's own resume args: --resume <id>, -r <id> or --resume=<id> for Claude Code (a bare --resume opens the picker and doesn't count), resume <id> for Codex. supervise uses it instead of knowing about Claude.
• When the pre-launch switch happens and the args resume a session, seats finds the conversation on the start seat (sessions.find), copies it to the next seat with copyTranscript, the same way the mid-session switch does, and launches there with the same args.
• When it can't be copied (not found, or a source without failover, i.e. Codex, whose conversations aren't confirmed to resume on another account), seats stays on the named seat and says in one line that it's at its limit, so you land on your conversation instead of an empty one.
• Launches that don't resume anything switch exactly as before.
• Tests in test/commands/run.test.ts with the fake claude: conversation copied and resumed on the next seat; not found, so it stays with the message; resumedId for both tools. The README's auto-switch section has a sentence on it.

This was meant for #18 but was pushed after #18 was squash-merged, so it's cherry-picked onto main here.

User-facing changes

BEGIN_COMMIT_OVERRIDE
fix(run): with auto-switch on, resuming a conversation on a seat at its limit carries it to the next seat, or opens it where it is when it can't move
END_COMMIT_OVERRIDE

Type of change

• Bug fix
• New provider
• New feature
• Docs / metadata

Checklist

• bun run check passes (Biome lint and format, typecheck, tests)
• bun src/cli.ts help runs without errors
• Changes to seat folders were tried with --dry-run or a throwaway HOME
• A new provider (if added) lives in src/providers/<id>/ and is listed in src/providers/index.ts