feat: remember agent cli options when resuming sessions

[dhh]

Native agent session restore rebuilt the resume command from the session reference alone, so a pane started as claude --permission-mode bypassPermissions came back as plain claude --resume <id> with default permissions.

What changed

Capture — the foreground process probe already reads each process's argv, so when it identifies an agent it now also extracts the command line after the agent token (detect::agent_launch_args_in_job, which handles wrapped invocations like node .../cli.js --flag). A new AgentLaunchArgsDetected event records it on the terminal, deduped so it fires once per change rather than once per probe.

Persist — a new optional agent_launch: {agent, args} field on the pane snapshot, stored per agent so a pane that later ran a different agent never resumes with the previous agent's options.

Replay — agent_resume::plan_with_launch_args() appends the surviving options after the session reference. src/agent_launch_args.rs decides what survives, with two rules:

• Options that select a conversation or a one-shot run are dropped, per agent (--resume, --continue, --session, --print, --prompt). Herdr supplies its own session reference.
• A bare word is kept only when it directly follows a kept option, where it is that option's value. Bare words elsewhere are prompts, subcommands, or positional paths.

Everything else is replayed, including options Herdr has never heard of, so a new flag in a future agent release survives a resume without anyone touching Herdr.

The second rule is what makes the first one cheap: the value of a dropped option disappears for free, because it is a bare word following no kept option. --resume <id> loses the id without Herdr knowing that --resume takes one. The same falls out for agents that select a session through a subcommand and a positional id, so codex resume <id> --full-auto needs no special case.

That also stops a resume from compounding: after Herdr resumes a pane once, the live process argv contains the --resume <id> Herdr itself appended, and the next restore drops it before adding the current one.

Deliberate limits

• An option given several separate values keeps the first: --add-dir /a /b resumes as --add-dir /a.
• A prompt written directly after a flag cannot be told apart from that flag's value, so it is replayed. claude "fix the bug" and a prompt following a value are both dropped; claude --dangerously-skip-permissions "fix the bug" is not.

Both are documented in the module and on the session-state docs page.

Verification

cargo nextest run green (3376 passed), fmt and clippy clean.

Verified live against a throwaway herdr-dev session on the debug build:

• a pane agent started as claude --permission-mode bypassPermissions recorded agent_launch: {agent: "claude", args: ["--permission-mode", "bypassPermissions"]} in session.json
• a snapshot seeded with session ref verify-session-id and args ["--model", "sonnet", "--resume", "stale-session", "some prompt"] resumed as hermes --resume verify-session-id --model sonnet — option replayed, stale session flag and its id dropped, trailing prompt left behind

Commits

The first commit carried per-agent tables of every option and its arity, used to tell a flag's value apart from a prompt. The second deletes them (573 lines) once the bare-word rule made them unnecessary. Reviewing the two together shows the reasoning; the end state is the second.

[dhh]

Moved upstream to herdrdev#2614. Leaving the branch in place: omarchy-pkgs pins commit 4fa315e for the herdr 0.8.0.r8 build, so the archive URL must keep resolving.