Changing dark mode setting revokes host agent API tokens.

[philco911]

Description
It looks like changing the dark mode setting revokes API tokens. I don't understand the connection between the two so maybe it's not related but I recreated it after remembering that I had changed the dark mode setting before having my hosts unauthenticated.

To Reproduce
Steps to reproduce the behavior:

1. Start with a clean install, with one Proxmox node attached.
2. Have no API tokens.
3. Add two hosts, each with their own agent scoped token.
4. Go to Settings->General and turn on, then off, the dark mode setting.
5. Go to the API token page and observe the host API tokens are gone (and they are really revoked since the hosts will get blocked on next update), and there is now a single "Environment" API token.

Expected behavior
The host API tokens not being revoked.

Environment:

• Pulse Version: 4.27.1
• Installation Type: ProxmoxVE LXC

[rcourtman]

Confirmed the bug. Saving a preference rewrote .env, the watcher saw API_TOKEN still present, and it replaced every scoped token with the fallback Environment record.

Fix shipped in two parts. Commit 5d99fc2 skips the .env write entirely when the content would stay the same, so dark mode and other cosmetic settings no longer touch authentication files.

Commit accecdb put the real fix in place. On startup any API_TOKEN or API_TOKENS entries that are not already stored get imported into api_tokens.json as Migrated from .env records, then api_tokens.json becomes the source of truth. The watcher now ignores the legacy env values once the tokens exist in the JSON store, so UI-created tokens stay intact while the env copy remains for older automation.

This path keeps existing deployments working. Operators who still rely on env tokens will see them automatically migrated and can rotate them later through the UI. Both commits will be included in the next release.