revert(proxy): drop the 1-hour cache TTL option and TTL-bucketed write accounting

The forced 1-hour cache_control TTL (schema v14) was a mistake. Injected
breakpoints return to Anthropic's standard 5-minute TTL, caller-owned
markers are preserved verbatim instead of having their TTLs rewritten,
and the 5m/1h cache-write buckets are removed from usage parsing and
pricing (back to the single aggregate cache-creation rate). The cache
TTL selector is removed from the rectifier settings panel along with its
i18n keys in all four locales.

SCHEMA_VERSION returns to 13: the unreleased cache_creation_1h_tokens
column and the v13->v14 migration are removed. The feature never shipped
in a release and the introducing commit was never pushed, so no
databases were stamped v14 outside this machine (local DB verified at
user_version 13).

src-tauri/src/commands/settings.rs

@@ -661,15 +661,6 @@ pub async fn set_optimizer_config(
     state: tauri::State<'_, crate::AppState>,
     config: crate::proxy::types::OptimizerConfig,
 ) -> Result<bool, String> {
-    // Validate cache_ttl: only allow known values
-    match config.cache_ttl.as_str() {
-        "5m" | "1h" => {}
-        other => {
-            return Err(format!(
-                "Invalid cache_ttl value: '{other}'. Allowed values: '5m', '1h'"
-            ))
-        }
-    }
     state
         .db
         .set_optimizer_config(&config)