fix(db): loop-append dense unresolved-ref result rows; make stripped-salvage visible (#1558) (#1576)

Real-world validation of #1575 on indexes damaged by the released v1.5.0
binary surfaced both of these.

getUnresolvedReferencesByFiles chunked its INPUT under SQLite's parameter
limit but appended each chunk's RESULT rows with a spread — every row
becomes a call argument, so a dense recovery sync (the #1541 self-heal
re-indexing 919 files produced 234,440 rows) exceeded V8's argument limit
and killed resolution mid-sync with "Maximum call stack size exceeded",
leaving the graph 226k edges short until another sync resumed the orphans
(and that sweep resolves measurably worse than the batched path — see the
follow-up issue). The failed-ref retry loader had the identical pattern on
unbounded result rows. Both append with a loop now (#1558).

The #1575 stripped-salvage warning also never rendered: init's summary
prints only index_partial warnings and counts only hard errors, so a run
with salvaged files still read as fully clean — and with no hard errors the
detail wasn't written to errors.log either. Salvage entries now carry code
'salvaged_stripped', the summary prints a visible warning naming the files,
and errors.log is written for salvage-only runs.

Validated on real corpora with full-graph dumps: healthy-path inits stay
byte-identical to the pre-#1575 baseline (cpython Lib, Alamofire, with a
determinism control); a realistically-damaged index (41 wiped + 5 missing
files, damage generated by the released binary) heals in one plain sync to
identical per-file counts and an edge set within the normal incremental
residual; pathological mass damage (52% of the repo) completes without
crashing. New regression test reproduces the RangeError on the old code
with 200k pending refs.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

src/extraction/index.ts

@@ -2102,6 +2102,7 @@ export class ExtractionOrchestrator {
             // on, and a silently "clean" file here is how an index quietly
             // disagrees with a later per-file sync of the same bytes (#1565).
             errEntry.severity = 'warning';
+            errEntry.code = 'salvaged_stripped';
             errEntry.message = `Indexed from comment-stripped source after repeated parse failures (symbols may be incomplete until the file is re-indexed): ${errEntry.message}`;
             filesErrored--;
             filesIndexed++;