app-server: source /feedback logs from sqlite at trace level (#12969)

## Summary
- write app-server SQLite logs at TRACE level when SQLite is enabled
- source app-server `/feedback` log attachments from SQLite for the
requested thread when available
- flush buffered SQLite log writes before `/feedback` queries them so
newly emitted events are not lost behind the async inserter
- include same-process threadless SQLite rows in those `/feedback` logs
so the attachment matches the process-wide feedback buffer more closely
- keep the existing in-memory ring buffer fallback unchanged, including
when the SQLite query returns no rows

## Details
- add a byte-bounded `query_feedback_logs` helper in `codex-state` so
`/feedback` does not fetch all rows before truncating
- scope SQLite feedback logs to the requested thread plus threadless
rows from the same `process_uuid`
- format exported SQLite feedback lines with the log level prefix to
better match the in-memory feedback formatter
- add an explicit `LogDbLayer::flush()` control path and await it in
app-server before querying SQLite for feedback logs
- pass optional SQLite log bytes through `codex-feedback` as the
`codex-logs.log` attachment override
- leave TUI behavior unchanged apart from the updated `upload_feedback`
call signature
- add regression coverage for:
  - newest-within-budget ordering
  - excluding oversized newest rows
  - including same-process threadless rows
  - keeping the newest suffix across mixed thread and threadless rows
  - matching the feedback formatter shape aside from span prefixes
  - falling back to the in-memory snapshot when SQLite returns no logs
  - flushing buffered SQLite rows before querying

## Follow-up
- SQLite feedback exports still do not reproduce span prefixes like
`feedback-thread{thread_id=...}:`; there is a `TODO(ccunningham)` in
`codex-rs/state/src/log_db.rs` for that follow-up.

## Testing
- `cd codex-rs && cargo test -p codex-state`
- `cd codex-rs && cargo test -p codex-app-server`
- `cd codex-rs && just fmt`

codex-rs/app-server/src/message_processor.rs

@@ -54,6 +54,7 @@ use codex_core::models_manager::collaboration_mode_presets::CollaborationModesCo
 use codex_feedback::CodexFeedback;
 use codex_protocol::ThreadId;
 use codex_protocol::protocol::SessionSource;
+use codex_state::log_db::LogDbLayer;
 use futures::FutureExt;
 use tokio::sync::broadcast;
 use tokio::sync::watch;
@@ -154,6 +155,7 @@ pub(crate) struct MessageProcessorArgs {
     pub(crate) loader_overrides: LoaderOverrides,
     pub(crate) cloud_requirements: CloudRequirementsLoader,
     pub(crate) feedback: CodexFeedback,
+    pub(crate) log_db: Option<LogDbLayer>,
     pub(crate) config_warnings: Vec<ConfigWarningNotification>,
 }
 
@@ -169,6 +171,7 @@ impl MessageProcessor {
             loader_overrides,
             cloud_requirements,
             feedback,
+            log_db,
             config_warnings,
         } = args;
         let auth_manager = AuthManager::shared(
@@ -201,6 +204,7 @@ impl MessageProcessor {
             cli_overrides: cli_overrides.clone(),
             cloud_requirements: cloud_requirements.clone(),
             feedback,
+            log_db,
         });
         let config_api = ConfigApi::new(
             config.codex_home.clone(),