fix: prevent template dialog from closing when switching browser tabs

[zenojunior]

What is this PR about?

Fixes a bug where the Create from Template dialog closes by itself when the user switches to another browser tab (or another window) and comes back.

Root cause: AddTemplate rendered its Dialog (and its open state) inside the Create Service DropdownMenuContent, using onSelect={(e) => e.preventDefault()} to keep the menu open while the dialog was showing. When the tab regains focus, Radix treats the focus landing on the portalled dialog as an outside interaction and dismisses the dropdown. Since a closed DropdownMenuContent unmounts its children, the whole AddTemplate component — dialog included — gets unmounted, which looks like the modal "closing" on its own.

Fix (the pattern recommended by Radix/shadcn for dialogs inside menus):

• AddTemplate is now a controlled component (open / onOpenChange props) and no longer renders its own DropdownMenuItem trigger.
• The environment page renders the Template menu item inside the dropdown (it just sets the open state) and renders <AddTemplate /> as a sibling of the DropdownMenu, so it survives the menu closing.

As a side benefit, the dropdown now closes properly when the dialog opens, instead of staying open (invisible) behind the modal.

Note: other items in this menu (AddApplication, AddDatabase, AddCompose, etc.) follow the same nested-dialog pattern and are affected by the same issue. I kept this PR scoped to the Template dialog as reported, but I'm happy to apply the same fix to the other items in a follow-up if the maintainers want.

Verification: tsc --noEmit passes and biome check reports no new issues on the touched files (the 2 pre-existing lint warnings in add-template.tsx were left untouched to keep the diff focused).

Checklist

Before submitting this PR, please make sure that:

• You created a dedicated branch based on the canary branch.
• You have read the suggestions in the CONTRIBUTING.md file https://github.com/Dokploy/dokploy/blob/canary/CONTRIBUTING.md#pull-request
• You have tested this PR in your local instance. If you have not tested it yet, please do so before submitting. This helps avoid wasting maintainers' time reviewing code that has not been verified by you. (Opening as a draft — will test on a local instance and mark as ready once verified.)

Issues related (if applicable)

N/A — no existing issue found for this bug.

Screenshots (if applicable)

Repro steps (before): Project → Create Service → Template → switch to another browser tab → switch back → the dialog is gone. After this change the dialog stays open.