[Icewind52]

Tracking issue

Closes #8231

Why are the changes needed?

Follow-up to #8232, from this review comment. Bootstrap only enables dev mode when FLYTE_DEV is exactly True, so FLYTE_DEV=true silently starts the in-cluster manager. flyte start devbox already reads the value back case-insensitively.

What changes were proposed in this pull request?

• Match FLYTE_DEV against true case-insensitively (strings.EqualFold) in a small isDevMode() helper, consistent with the SDK.
• Add TestIsDevMode.
• Drop the case-sensitivity note added to CONTRIBUTING.md in docs: use FLYTE_DEV=True to enable devbox dev mode #8232.

How was this patch tested?

Unit tests: go test ./... in docker/devbox-bundled/bootstrap. TestIsDevMode covers True/true/TRUE (dev mode) and False/false/empty/1 (not dev mode); the true and TRUE cases fail against the previous == "True" check.

End-to-end:

1. make devbox-build from this branch, then make devbox-run FLYTE_DEV=true (lowercase) and make devbox-run FLYTE_DEV=True (Uppercase)
2. kubectl get pods -n flyte: no flyte-binary pod
3. make -C manager run and a hello-world run (1 parent + 10 child tasks): all 11 TaskActions completed; the manager log shows a single TaskAction controller and no Operation cannot be fulfilled conflicts

Labels

• fixed

Setup process

N/A

Screenshots

N/A

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

#8232

Stack

If you do use git town to manage PR Stacks, the stack relevant to this PR
will show below. Otherwise, you can ignore this section.

Docs link

N/A

[Icewind52]

tagging @pingsutw for review as this is a follow-up to #8232