perf(skill): make the codeman skill spawn workers instead of deliberating

Measured against a live 1.18.1 server, the API does the whole job in about ten
seconds: two cold claude workers spawned and ready in 6.3s, both tasked and both
answers read in 4.0s more. The slowness users reported was agent-side.

Three causes, all of them things the skill taught:

- It taught serial spawning. Nothing in the main document showed `&`/`wait`, so
  "spawn two workers" read as "do the readiness ladder twice", which is one model
  turn per worker.
- It had no spawn primitive. The happy path had to be reassembled on every run from
  where-to-spawn, a four-stage readiness ladder, send-and-wait, the fan-out caveats
  and a recipe with two variants. Each is a decision, and most carry a warning.
- It cost ~16k tokens before the first call, at 3.6:1 prose to code, with 25 warning
  glyphs and 55 occurrences of "never". A document that is mostly failure modes
  teaches caution, and caution bills as thinking tokens.

The preamble now defines the verbs rather than describing them: spawn_worker,
spawn_workers (concurrent), sendwait, last_text. Section 1 composes them into the
whole job in one Bash call and says to stop reading there.

Two ceremonies the measurements retired: the pid poll (one iteration, 33ms, and
wait-output already blocks on the composer) and reading settings.local.json to check
hooks for a case quick-start creates, which always has them. That check stays
required for linked cases and raw paths, where its absence silently breaks
send-and-wait.

The bootstrap's write condition now greps the version stamp, so a stale or truncated
preamble self-heals rather than failing and asking for a manual rm. The stamp line is
kept bare because the grep anchors on it with $; an inline comment there would rewrite
the file on every bootstrap.

Section 5 moved to reference/verbs.md behind an index, cutting the always-paid
SKILL.md from ~16.4k to ~7.6k tokens. Section numbers and anchor slugs are unchanged,
so existing references still resolve; all 201 anchors across the five files were
checked, with the checker positive-controlled against an injected bad link.

Verified by extracting the code blocks from the shipped file and running them against
the live server: bootstrap plus full fast path, two workers resolving on the
definitive stop signal, answers read and sessions deleted, in 6.8s.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

skills/codeman/reference/recipes.md

@@ -1,16 +1,27 @@
 # Worked orchestration flows
 
 Loaded on demand from the `codeman` skill. Every flow assumes the SKILL.md preamble is
-in scope (`$API`, `$SELF`, `$CID`, `"${CURL[@]}"`, `delete_session`); see
+in scope (`$API`, `$SELF`, `$CID`, `"${CURL[@]}"`, `delete_session`, plus the fast-path
+verbs `spawn_worker` / `spawn_workers` / `sendwait` / `last_text`); see
 [SKILL.md §0](../SKILL.md#0-guard-and-bootstrap) for it and
 [the safety rules](../SKILL.md#4-safety-rules) for what you may call unprompted.
 
+⚠️ **These flows are the long way round, and most jobs do not need them.** If the job is
+"spawn N claude workers, task them, collect the answers", [SKILL.md
+§1](../SKILL.md#1-the-fast-path-n-workers-one-bash-call) already is that job in one Bash
+call, measured at about 10 s for two cold workers end to end. Come here when you need a
+mechanism §1 does not cover: shell or otherwise hook-less workers (Flows 2, 3), a worker
+stuck on a permission dialog (Flow 5), messaging (Flow 6), or real work in git worktrees
+(Flow 7). The flows below spell each step out because they are teaching the mechanism;
+spelling them out again when §1 would have done is the most common way an agent turns a
+ten-second run into a multi-minute one.
+
 ⚠️ **Shell state does not survive between tool calls**, so every Bash call below opens
 by sourcing the preamble file the §0 bootstrap wrote, and checking its version stamp:
 
 ```bash
 . "${XDG_CACHE_HOME:-$HOME/.cache}/codeman-agent-$CODEMAN_SESSION_ID.sh" 2>/dev/null
-[ "${CODEMAN_PREAMBLE:-}" = 1.17.0 ] || { echo "preamble missing or stale; re-run the §0 bootstrap"; exit 1; }
+[ "${CODEMAN_PREAMBLE:-}" = 1.19.0 ] || { echo "preamble missing or stale; re-run the §0 bootstrap"; exit 1; }
 ```
 
 Do **not** re-paste the preamble body into each call. Sourcing it is what retires the
@@ -272,16 +283,16 @@ live (and one anti-pattern, measured failing, replaced by B):
 **A. Background the send-and-waits** (simplest; each resolved on `stop` while the
 other was still running). Each send costs its worker one billed turn:
 
+`sendwait <sid> <prompt> [seq]` is a preamble function ([SKILL.md
+§0](../SKILL.md#0-guard-and-bootstrap)); it applies the `\r` and a per-worker `clientId`,
+so do not redefine it here. Background one call per worker and `wait`:
+
 ```bash
-sendwait() {  # $1=sid $2=prompt $3=seq, assumes the worker passed Flow 1's readiness
-  local body; body=$(jq -n --arg p "$2" --argjson s "$3" --arg c "codeman-fan-$1" \
-    '{input:($p+"\r"),useMux:true,clientId:$c,seq:$s,wait:true,waitTimeout:600000}')
-  "${CURL[@]}" -X POST "$API/api/v1/sessions/$1/input" \
-    -H 'Content-Type: application/json' --data-binary "$body" > "/tmp/fan-$1.json"
-}
-( sendwait "$SID1" 'refactor module A and reply DONE' 2 & \
-  sendwait "$SID2" 'write tests for module B and reply DONE' 2 & wait )
-jq -c '.data.wait | {signal, waitedMs}' /tmp/fan-"$SID1".json /tmp/fan-"$SID2".json
+D=$(mktemp -d)   # a function's stdout is per-worker, so collect it in files, not a var
+sendwait "$SID1" 'refactor module A and reply DONE' > "$D/1" &
+sendwait "$SID2" 'write tests for module B and reply DONE' > "$D/2" &
+wait
+jq -c '.data.wait | {signal, waitedMs}' "$D/1" "$D/2"; rm -rf "$D"
 ```
 
 One in-flight wait per worker keeps you far from the 16-per-session waiter cap.