test(context-budget): raise the capy/skill/gstack eager ceiling to its captured value (own-jam meter contract and RESERVATION_ID prose, GSTA-167)

CI at 3e819f1: eagerPerInvocation.capy/skill/gstack 4742 tok > limit 4588.
Only this ceiling moves; capture-context-budget's value for it is 5217.

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

test/fixtures/context-budget.json

@@ -9,7 +9,7 @@
     "browser-skills/hackernews-frontpage": 371,
     "canary": 7738,
     "captain": 6551,
-    "capy/skill/gstack": 4588,
+    "capy/skill/gstack": 5217,
     "careful": 1239,
     "codex": 9890,
     "context-restore": 6287,