Merge PR #149: Add --no-db mode for JSONL-only operation

Implements --no-db mode to avoid SQLite corruption in multi-process scenarios.

Changes:
- Add in-memory storage backend (internal/storage/memory/)
- Add JSONL persistence layer (cmd/bd/nodb.go)
- Integrate --no-db flag into command flow
- Support config.yaml for no-db and issue-prefix settings
- Refactor atomic JSONL writes into shared helper

Co-authored-by: rrnewton <rrnewton@users.noreply.github.com>
Amp-Thread-ID: https://ampcode.com/threads/T-67d6d80f-27dc-490a-a95d-61ad06d5b06d
Co-authored-by: Amp <amp@ampcode.com>

internal/config/config.go

@@ -71,8 +71,10 @@ func Initialize() error {
 	v.SetDefault("no-daemon", false)
 	v.SetDefault("no-auto-flush", false)
 	v.SetDefault("no-auto-import", false)
+	v.SetDefault("no-db", false)
 	v.SetDefault("db", "")
 	v.SetDefault("actor", "")
+	v.SetDefault("issue-prefix", "")
 	
 	// Additional environment variables (not prefixed with BD_)
 	// These are bound explicitly for backward compatibility