test: raise the capy skill's eager context ceiling for the R75 stale-pin prose (GST-1642)

The R75 rules grew capy/skill/gstack/SKILL.md to 5491 tokens, past its 5315 ceiling; free-tests run 42251052228 failed test/context-budget-ratchet.test.ts. Per the ratchet protocol this records the capture's value (actual x 1.10 = 6041) for this skill only; every other ceiling is unchanged. Gate disposition left open for the owner.

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": 5315,
+    "capy/skill/gstack": 6041,
     "careful": 1239,
     "codex": 9890,
     "context-restore": 6287,