build: replace kit with Tilt for local development and CI

[Joibel]

Draft PR to exercise CI on the fork before proposing upstream.

Replaces kit (tasks.yaml) with Tilt for local dev and CI e2e. See the commit message for the full breakdown. Key CI changes under test here:

• e2e jobs build and deploy via tilt up -- --mode=ci, kept running through the test steps so Tilt's port-forwards serve the tests (replaces kubeauto); readiness gated on tilt wait
• use-api / secure / retries matrix keys are honoured again (--api, --secure + HTTPS probe patch, TEST_RETRIES)
• Tilt and k3d pinned via the Makefile (renovate-managed)
• kubelet image-GC protection applied by hack/tilt/k3d-up.sh

🤖 Generated with Claude Code

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