Align SQLite feedback logs with feedback formatter (#13494)

## Summary
- store a pre-rendered `feedback_log_body` in SQLite so `/feedback`
exports keep span prefixes and structured event fields
- render SQLite feedback exports with timestamps and level prefixes to
match the old in-memory feedback formatter, while preserving existing
trailing newlines
- count `feedback_log_body` in the SQLite retention budget so structured
or span-prefixed rows still prune correctly
- bound `/feedback` row loading in SQL with the retention estimate, then
apply exact whole-line truncation in Rust so uploads stay capped without
splitting lines

## Details
- add a `feedback_log_body` column to `logs` and backfill it from
`message` for existing rows
- capture span names plus formatted span and event fields at write time,
since SQLite does not retain enough structure to reconstruct the old
formatter later
- keep SQLite feedback queries scoped to the requested thread plus
same-process threadless rows
- restore a SQL-side cumulative `estimated_bytes` cap for feedback
export queries so over-retained partitions do not load every matching
row before truncation
- add focused formatting coverage for exported feedback lines and parity
coverage against `tracing_subscriber`

## Testing
- cargo test -p codex-state
- just fix -p codex-state
- just fmt

codex author: `codex resume 019ca1b0-0ecc-78b1-85eb-6befdd7e4f1f`

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/core/tests/suite/sqlite_state.rs

@@ -482,7 +482,7 @@ async fn tool_call_logs_include_thread_id() -> Result<()> {
         if let Some(row) = rows.into_iter().find(|row| {
             row.message
                 .as_deref()
-                .is_some_and(|m| m.starts_with("ToolCall:"))
+                .is_some_and(|m| m.contains("ToolCall:"))
         }) {
             let thread_id = row.thread_id;
             let message = row.message;
@@ -497,7 +497,7 @@ async fn tool_call_logs_include_thread_id() -> Result<()> {
     assert!(
         message
             .as_deref()
-            .is_some_and(|text| text.starts_with("ToolCall:")),
+            .is_some_and(|text| text.contains("ToolCall:")),
         "expected ToolCall message, got {message:?}"
     );