feat: add session log usage tracking without proxy

Parse Claude Code JSONL session files (~/.claude/projects/) and Codex
SQLite database (~/.codex/state_5.sqlite) to track API usage without
requiring proxy interception. This enables usage statistics for users
who don't use the proxy feature.

Key changes:
- Add session_usage.rs: incremental JSONL parser with message.id dedup
- Add session_usage_codex.rs: import thread-level token data from Codex
- Add data_source column to proxy_request_logs (proxy/session_log/codex_db)
- Add session_log_sync table for tracking parse offsets
- Background sync every 60s + manual sync via DataSourceBar UI
- Schema migration v7→v8
- i18n support for zh/en/ja

src/components/usage/RequestLogTable.tsx

@@ -371,13 +371,16 @@ export function RequestLogTable({ refreshIntervalMs }: RequestLogTableProps) {
                   <TableHead className="whitespace-nowrap">
                     {t("usage.status")}
                   </TableHead>
+                  <TableHead className="whitespace-nowrap">
+                    {t("usage.source", { defaultValue: "Source" })}
+                  </TableHead>
                 </TableRow>
               </TableHeader>
               <TableBody>
                 {logs.length === 0 ? (
                   <TableRow>
                     <TableCell
-                      colSpan={11}
+                      colSpan={12}
                       className="text-center text-muted-foreground"
                     >
                       {t("usage.noData")}
@@ -506,6 +509,21 @@ export function RequestLogTable({ refreshIntervalMs }: RequestLogTableProps) {
                           {log.statusCode}
                         </span>
                       </TableCell>
+                      <TableCell>
+                        {log.dataSource && log.dataSource !== "proxy" ? (
+                          <span className="inline-flex rounded-full px-2 py-0.5 text-[10px] bg-indigo-100 text-indigo-800">
+                            {t(`usage.dataSource.${log.dataSource}`, {
+                              defaultValue: log.dataSource,
+                            })}
+                          </span>
+                        ) : (
+                          <span className="inline-flex rounded-full px-2 py-0.5 text-[10px] bg-gray-100 text-gray-600">
+                            {t("usage.dataSource.proxy", {
+                              defaultValue: "Proxy",
+                            })}
+                          </span>
+                        )}
+                      </TableCell>
                     </TableRow>
                   ))
                 )}