fix(usage): account for cache-write tokens across schema versions

Parse cache_write_tokens from OpenAI usage details and preserve cache creation data across Chat, Responses, and Anthropic conversion paths.

Add explicit input-token semantics to request logs and rollups so legacy rows subtract cache reads only while new total-inclusive rows subtract both cache reads and writes. Migrate v12 databases, normalize rollups to fresh input, and cover historical backfill behavior with regression tests.

src-tauri/src/proxy/usage/logger.rs

@@ -4,6 +4,7 @@ use super::calculator::{CostBreakdown, CostCalculator, ModelPricing};
 use super::parser::TokenUsage;
 use crate::database::{Database, PRICING_SOURCE_REQUEST, PRICING_SOURCE_RESPONSE};
 use crate::error::AppError;
+use crate::services::sql_helpers::{INPUT_TOKEN_SEMANTICS_FRESH, INPUT_TOKEN_SEMANTICS_TOTAL};
 use crate::services::usage_stats::{find_model_pricing_row, is_placeholder_pricing_model};
 use rust_decimal::Decimal;
 use std::str::FromStr;
@@ -70,15 +71,21 @@ impl<'a> UsageLogger<'a> {
             };
 
         let created_at = chrono::Utc::now().timestamp();
+        let input_token_semantics = if matches!(log.app_type.as_str(), "codex" | "gemini") {
+            INPUT_TOKEN_SEMANTICS_TOTAL
+        } else {
+            INPUT_TOKEN_SEMANTICS_FRESH
+        };
 
         conn.execute(
             "INSERT OR REPLACE INTO proxy_request_logs (
                 request_id, provider_id, app_type, model, request_model, pricing_model,
                 input_tokens, output_tokens, cache_read_tokens, cache_creation_tokens,
+                input_token_semantics,
                 input_cost_usd, output_cost_usd, cache_read_cost_usd, cache_creation_cost_usd, total_cost_usd,
                 latency_ms, first_token_ms, status_code, error_message, session_id,
                 provider_type, is_streaming, cost_multiplier, created_at
-            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13, ?14, ?15, ?16, ?17, ?18, ?19, ?20, ?21, ?22, ?23, ?24)",
+            ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10, ?11, ?12, ?13, ?14, ?15, ?16, ?17, ?18, ?19, ?20, ?21, ?22, ?23, ?24, ?25)",
             rusqlite::params![
                 log.request_id,
                 log.provider_id,
@@ -90,6 +97,7 @@ impl<'a> UsageLogger<'a> {
                 log.usage.output_tokens,
                 log.usage.cache_read_tokens,
                 log.usage.cache_creation_tokens,
+                input_token_semantics,
                 input_cost,
                 output_cost,
                 cache_read_cost,