Match ComfyUI's dependency floors (#604) and fix the stalled store test race (#603) (#606)

* chore(deps): match ComfyUI's Pillow, aiohttp and numpy floors (#604)

PromptManager never fights ComfyUI on versions: the floors follow its
requirements.txt and Dependabot no longer raises them. The full suite passes on
Pillow 10.1.0 and aiohttp 3.11.8; numpy was tested at 1.26.4, the first with
Python 3.12 wheels. A test that left response bodies unread hung the aiohttp
client before 3.11.11, so it reads them now.

* test(thumbnails): the stalled store call test runs without the probe (#603)

note_failure() wakes the probe, which finds the healthy test folder again at
once, so the next lookup could do store I/O and the test failed intermittently.

.github/dependabot.yml

@@ -17,6 +17,11 @@ updates:
       prefix: "deps(pip)"
       include: "scope"
     rebase-strategy: "auto"
+    # These floors follow ComfyUI's requirements.txt, never the newest release.
+    ignore:
+      - dependency-name: "Pillow"
+      - dependency-name: "aiohttp"
+      - dependency-name: "numpy"
     # Optional: group non-breaking updates to reduce PR noise
     groups:
       python-minor-and-patch: