feat(p10-1a-1): add IngestReport skip counters + SkipExamples

Adds five new u32 counters (skipped_gitignore, skipped_kebabignore,
skipped_builtin_blacklist, skipped_generated, skipped_size_exceeded)
and a SkipExamples struct (≤5 sample paths per category) to
IngestReport. All new fields are #[serde(default)] for backward-compat
deserialization. Downstream literal construction sites patched with
zeros/empty; snapshot re-baked.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/kebab-store-sqlite/tests/ingest_report_snapshot.rs

@@ -35,6 +35,12 @@ fn fixture_report() -> IngestReport {
         errors: 0,
         duration_ms: 187,
         skipped_by_extension: std::collections::BTreeMap::new(),
+        skipped_gitignore: 0,
+        skipped_kebabignore: 0,
+        skipped_builtin_blacklist: 0,
+        skipped_generated: 0,
+        skipped_size_exceeded: 0,
+        skip_examples: kebab_core::SkipExamples::default(),
         items: Some(vec![
             IngestItem {
                 kind: IngestItemKind::New,