ship: name the pre-push guards in Step 17 and the early push (moved from #3923 per GSTA-258)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

test/fixtures/golden/agy-ship-SKILL.md

@@ -872,7 +872,7 @@ A new PR or an existing draft needs no question: Step 19 creates or keeps the dr
 ```
 
 It checks the branch, the offer, the gate above (`--gate-open <n>`; `--gate-open-approved` is B)
-and `gstack-pregate sealed`, then `git ls-remote --heads origin refs/heads/<branch-name>` against HEAD: a failed lookup STOPs, a match prints
+`gstack-pregate sealed` and the guards (`GUARDS:`), then `git ls-remote` of `<branch-name>` against HEAD: a failed lookup STOPs, a match prints
 `PUSH: ALREADY_PUSHED` (go to Step 18), else it runs `git push -u origin <branch-name>`.
 
 **If the push fails, STOP.** No Step 19 or publication claim. Report the error:

test/fixtures/golden/claude-ship-SKILL.md

@@ -871,7 +871,7 @@ A new PR or an existing draft needs no question: Step 19 creates or keeps the dr
 ```
 
 It checks the branch, the offer, the gate above (`--gate-open <n>`; `--gate-open-approved` is B)
-and `gstack-pregate sealed`, then `git ls-remote --heads origin refs/heads/<branch-name>` against HEAD: a failed lookup STOPs, a match prints
+`gstack-pregate sealed` and the guards (`GUARDS:`), then `git ls-remote` of `<branch-name>` against HEAD: a failed lookup STOPs, a match prints
 `PUSH: ALREADY_PUSHED` (go to Step 18), else it runs `git push -u origin <branch-name>`.
 
 **If the push fails, STOP.** No Step 19 or publication claim. Report the error:

test/fixtures/golden/codex-ship-SKILL.md

@@ -878,7 +878,7 @@ $GSTACK_ROOT/bin/gstack-ship-release push --branch <branch-name>
 ```
 
 It checks the branch, the offer, the gate above (`--gate-open <n>`; `--gate-open-approved` is B)
-and `gstack-pregate sealed`, then `git ls-remote --heads origin refs/heads/<branch-name>` against HEAD: a failed lookup STOPs, a match prints
+`gstack-pregate sealed` and the guards (`GUARDS:`), then `git ls-remote` of `<branch-name>` against HEAD: a failed lookup STOPs, a match prints
 `PUSH: ALREADY_PUSHED` (go to Step 18), else it runs `git push -u origin <branch-name>`.
 
 **If the push fails, STOP.** No Step 19 or publication claim. Report the error:

test/fixtures/golden/factory-ship-SKILL.md

@@ -880,7 +880,7 @@ $GSTACK_ROOT/bin/gstack-ship-release push --branch <branch-name>
 ```
 
 It checks the branch, the offer, the gate above (`--gate-open <n>`; `--gate-open-approved` is B)
-and `gstack-pregate sealed`, then `git ls-remote --heads origin refs/heads/<branch-name>` against HEAD: a failed lookup STOPs, a match prints
+`gstack-pregate sealed` and the guards (`GUARDS:`), then `git ls-remote` of `<branch-name>` against HEAD: a failed lookup STOPs, a match prints
 `PUSH: ALREADY_PUSHED` (go to Step 18), else it runs `git push -u origin <branch-name>`.
 
 **If the push fails, STOP.** No Step 19 or publication claim. Report the error:

test/size-ledger/ship/gsta258-l6-guard-carry.json

@@ -0,0 +1,4 @@
+{
+  "bytes": 4,
+  "why": "GST-1138: ship names the pre-push guards in Step 17 and the early push (GUARDS:), with the ls-remote line shortened to fit"
+}