fix(proxy): add stable usage keys and idempotent raw-response logging

Derive request ids from upstream envelope ids (Codex/OpenAI top-level
id, Gemini responseId, Claude message id with non-empty filtering)
scoped as session:{app_type}:{provider_id}:{id} for non-Claude sources;
Claude keeps bare session:{id} to preserve session-log convergence.

The logger now queries and conditionally writes under a single
connection guard: identical semantic replays return without writing or
notifying, session_log rows may be upgraded by proxy, and same-id
different-semantic responses land on a deterministic SHA-256 collision
fallback key instead of being overwritten. Fixes the random-UUID
INSERT OR REPLACE duplication behind #5496.

src-tauri/src/proxy/providers/transform.rs

@@ -1181,7 +1181,7 @@ mod tests {
             Some("chatcmpl-claude-compatible")
         );
         assert_eq!(
-            usage.dedup_request_id(),
+            usage.dedup_request_id(None),
             "session:chatcmpl-claude-compatible"
         );
     }