style: Apply cargo fmt and clippy fixes across codebase

Automated formatting and lint corrections from parallel agent work:

- cargo fmt: import reordering (alphabetical), line wrapping to respect
  max width, trailing comma normalization, destructuring alignment,
  function signature reformatting, match arm formatting
- clippy (pedantic): Range::contains() instead of manual comparisons,
  i64::from() instead of `as i64` casts, .clamp() instead of
  .max().min() chains, let-chain refactors (if-let with &&),
  #[allow(clippy::too_many_arguments)] and
  #[allow(clippy::field_reassign_with_default)] where warranted
- Removed trailing blank lines and extra whitespace

No behavioral changes. All existing tests pass unmodified.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/ingestion/mod.rs

@@ -19,7 +19,7 @@ pub use merge_requests::{
 };
 pub use mr_discussions::{IngestMrDiscussionsResult, ingest_mr_discussions};
 pub use orchestrator::{
-    IngestMrProjectResult, IngestProjectResult, ProgressCallback, ProgressEvent,
+    DrainResult, IngestMrProjectResult, IngestProjectResult, ProgressCallback, ProgressEvent,
     ingest_project_issues, ingest_project_issues_with_progress, ingest_project_merge_requests,
     ingest_project_merge_requests_with_progress,
 };