docs: finish dropping the stripped-newline rule from the input docs

The first commit left the old rule standing in places: the gotchas list in
extending-codeman.md still said newlines were stripped and that
"echo A\necho B\r" ran `echo Aecho B`, and so did both READMEs and the
skill's big-input section. Those now describe the paste.

Newlines are only kept on the mux path, so the docs that describe the paste
say "with useMux": without it a multi-line body is not a plain prompt and is
written straight into the pane.

Cron keeps rejecting multi-line prompts, but its docs and the code comments
in cron-service.ts, schemas.ts and respawn-controller.ts gave a reason this
change removes (writeViaMux joining lines, a newline submitting in Ink). The
reason that remains is the submit check, which cannot recognise a
multi-line paste in the composer, and for cron's paste mode the newlines
reaching the CLI as keys.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

plugins/codeman/skills/codeman/reference/endpoints.md

@@ -420,8 +420,9 @@ callers send no body at all.
   **or Enter is never sent**: the text is typed onto the worker's prompt and sits
   there unsubmitted. This is [symptom 1](#1-deliveredtrue-then-every-wait-times-out),
   the number-one silent failure.
-- Newlines in `input` are kept: the text goes in as one bracketed paste and the `\r`
-  submits all lines. To send a bare Enter (confirm a dialog), send `{"input":"\r"}`.
+- With `useMux`, newlines in `input` are kept: the text goes in as one bracketed paste
+  and the `\r` submits all lines (without `useMux`, multi-line input is written straight
+  into the pane). To send a bare Enter (confirm a dialog), send `{"input":"\r"}`.
 - `input` is capped at **65536** characters. ⚠️ **Two caps disagree and the smaller one
   is the real one**: the Zod schema allows 100000 (`schemas.ts:1035`), so a 65537-to-100000
   character body passes validation and *then* 400s at the route against

plugins/codeman/skills/codeman/reference/verbs.md

@@ -303,10 +303,11 @@ duplicate resend costs nothing.
 Codeman types the text and sends Enter **only when the input contains a carriage
 return**; without it your command sits unsubmitted on the worker's prompt and
 everything downstream times out. No response field catches this: `delivered:true`
-means "written to the pane", **not** "submitted". Newlines are kept: the text goes in
-as one paste, and the `\r` submits all of it. Build the body with `jq -n` for any prompt you did not
-author as a literal, because the inline `-d '{"input":"'"$P"'\r"}'` pattern breaks on
-the first double quote, backslash or `$` in a real prompt:
+means "written to the pane", **not** "submitted". With `useMux`, newlines are kept: the
+text goes in as one paste, and the `\r` submits all of it. Build the body with `jq -n`
+for any prompt you did not author as a literal, because the inline
+`-d '{"input":"'"$P"'\r"}'` pattern breaks on the first double quote, backslash or `$`
+in a real prompt:
 
 ```bash
 BODY=$(jq -n --arg p "$PROMPT" '{input:($p+"\r"),useMux:true,clientId:"agent-1",seq:1,wait:true,waitTimeout:60000}')
@@ -587,9 +588,9 @@ allowlist in §4.
 
 ### 5.9 Big input via the workspace
 
-The composer is a single line capped at 65536 characters with newlines stripped, which
-makes it a bad channel for a spec, a diff or a file list. The workspace is the good
-one, and for a local or docker case you are on the same filesystem as the worker.
+The composer is capped at 65536 characters, and a multi-line paste cannot be confirmed
+as submitted, which makes it a bad channel for a spec, a diff or a file list. The
+workspace is the good one, and for a local or docker case you are on the same filesystem as the worker.
 
 1. Write `TASK.md` into the worker's workspace with your own file tools. The path is
    `.data.casePath` from `quick-start`, or the `workingDir` you passed to