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/snapshots/ingest_report.snapshot.json

@@ -42,8 +42,19 @@
     ],
     "root": "/home/u/KB"
   },
+  "skip_examples": {
+    "builtin_blacklist": [],
+    "generated": [],
+    "gitignore": [],
+    "size_exceeded": []
+  },
   "skipped": 0,
+  "skipped_builtin_blacklist": 0,
   "skipped_by_extension": {},
+  "skipped_generated": 0,
+  "skipped_gitignore": 0,
+  "skipped_kebabignore": 0,
+  "skipped_size_exceeded": 0,
   "unchanged": 0,
   "updated": 1
 }