fix(#4113): add no-op to empty then-body in chunked-planning-mode.md's outline resume-check (#4125)

* fix(#4113): add no-op to empty then-body in chunked-planning-mode.md's outline resume-check

The `### 8.5.1 Outline Phase` resume-detection `if` block only contained a
comment in its `then` clause, which is a syntax error under both bash and
zsh if executed literally. The workflow ShellCheck lint added by #4109
already flags this (SC1009/1048/1072/1073/2105) but the findings were
masked by matching entries in the pre-existing-findings baseline; those
five entries are removed here so a regression re-surfaces as a new
failure instead of being silently re-absorbed.

* chore: backfill changeset PR number for #4125

* fix(#4113): fix second empty-then/continue-outside-loop defect surfaced by baseline cleanup

Removing the 5 stale baseline entries for chunked-planning-mode.md in the
prior commit unmasked a second, genuinely separate ShellCheck finding
(SC2105) in a different fenced block of the same file: a bare `continue`
outside any bash loop in the ### 8.5.2 per-plan resume-check. Same root
cause class as the original bug (pseudocode fenced as literal bash) —
fixed the same way, with a `:` no-op preserving the documentation.

---------

Co-authored-by: sim <sim@local>

scripts/lint-workflow-shellcheck-baseline.json

@@ -629,31 +629,6 @@
     "code": "2235",
     "message": "Use { ..; } instead of (..) to avoid subshell overhead."
   },
-  {
-    "file": "gsd-core/workflows/plan-phase/steps/chunked-planning-mode.md",
-    "code": "1009",
-    "message": "The mentioned syntax error was in this if expression."
-  },
-  {
-    "file": "gsd-core/workflows/plan-phase/steps/chunked-planning-mode.md",
-    "code": "1048",
-    "message": "Can't have empty then clauses (use 'true' as a no-op)."
-  },
-  {
-    "file": "gsd-core/workflows/plan-phase/steps/chunked-planning-mode.md",
-    "code": "1072",
-    "message": "Unexpected keyword/token. Fix any mentioned problems and try again."
-  },
-  {
-    "file": "gsd-core/workflows/plan-phase/steps/chunked-planning-mode.md",
-    "code": "1073",
-    "message": "Couldn't parse this then clause. Fix to allow more checks."
-  },
-  {
-    "file": "gsd-core/workflows/plan-phase/steps/chunked-planning-mode.md",
-    "code": "2105",
-    "message": "continue is only valid in loops."
-  },
   {
     "file": "gsd-core/workflows/plan-phase/steps/stall-detection-helpers.md",
     "code": "2086",