fix: app cache and other issues (#5460)

* fixes

* #[serde(untagged)] my BEHATED (still kinda broken)

* remove unused hasContent ref

* clean up code in fetch instance

* ping 3 times for average latency

* fix: pinging to be more accurate

TCP_NODELAY — Set on the TCP stream right after connect, preventing Nagle's algorithm from buffering the small ping packet (could save up to ~40ms)

Instant over Utc::now() — Switched to monotonic std::time::Instant for timing, which is more precise and designed for measuring elapsed time (still using chrono just for the ping magic value)

* delete useFetch util and just use native fetch

* rename worlds until functions for more clarity

* fix lint

* fix cache.rs logic

* make backend ping use both impls

* Add optional timeout to server ping

* fix gallery appearing in nav with no items

* remove EU countries and add EU option for server country

* add uk to europe

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Co-authored-by: aecsocket <aecsocket@tutanota.com>

Cargo.toml

@@ -179,7 +179,7 @@ tauri = "2.8.5"
 tauri-build = "2.4.1"
 tauri-plugin-deep-link = "2.4.3"
 tauri-plugin-dialog = "2.4.0"
-tauri-plugin-http = "2.5.2"
+tauri-plugin-http = "2.5.7"
 tauri-plugin-opener = "2.5.0"
 tauri-plugin-os = "2.3.1"
 tauri-plugin-single-instance = "2.3.4"