Clarify no-launch output flags

[gadflysu]

Problem

-n / --no-launch currently prints the selected session directory, while -n -v / --no-launch --verbose changes the output type to a full launch command.

That makes -v carry two responsibilities:

• verbose diagnostics/logging
• selecting the output format for no-launch mode

The combined -nv shorthand is especially unclear and does not need to remain compatible.

Requirement

Separate no-launch output format from verbosity:

• keep no-launch as an interactive select-without-launch workflow
• add an explicit directory-printing mode, e.g. --print-dir
• add an explicit command-printing mode, e.g. --print-launch-command
• stop documenting and preserving -nv as the full-command interface
• keep --verbose focused on diagnostics, not output type

Relationship To #3

#3's shell-init work needs a machine-readable launch-command output path. Earlier #3 drafts relied on -n -v; this issue should replace that dependency with --print-launch-command.

After #40, shell-init should call:

command aps --print-launch-command ...

not:

command aps --no-launch --verbose ...

Scope

• CLI parsing and help text
• launcher no-launch output selection
• README examples
• tests that cover output mode conflicts and selected-session behavior
• --claude-cmd path breaks Ctrl-Z job control #3 plan alignment for the shell-init output command

Non-Goals

• Do not skip picker selection by defaulting to the newest session.
• Do not change list mode output.
• Do not implement shell-init here; --claude-cmd path breaks Ctrl-Z job control #3 may consume --print-launch-command later.

Plan

See docs/agent/plan-issue-40-no-launch-output-flags.md.