Fix CI test failures (bd-1231)

- Always recompute content_hash in importer to avoid stale hashes from JSONL
- Add .gitignore to test repos to prevent database files from being tracked
- Fix daemon auto-import test to use correct RPC operation ('show' not 'get_issue')
- Set last_import_time metadata in test helper to enable staleness check
- Add filesystem settle delay after git pull in tests

Root cause: CloseIssue updates status but not content_hash, so importer
thought issues were unchanged. Always recomputing content_hash fixes this.

Amp-Thread-ID: https://ampcode.com/threads/T-63ef3a7d-8efe-472d-97ed-6ac95bd8318b
Co-authored-by: Amp <amp@ampcode.com>

internal/importer/importer.go

@@ -61,10 +61,9 @@ func ImportIssues(ctx context.Context, dbPath string, store storage.Storage, iss
 	}
 
 	// Compute content hashes for all incoming issues (bd-95)
+	// Always recompute to avoid stale/incorrect JSONL hashes (bd-1231)
 	for _, issue := range issues {
-		if issue.ContentHash == "" {
-			issue.ContentHash = issue.ComputeContentHash()
-		}
+		issue.ContentHash = issue.ComputeContentHash()
 	}
 
 	// Get or create SQLite store