[DoctorRemoteControl]

Database clients can now query rows as Jackson JSON nodes and bind JSON values through prepared statements using their existing PostgreSQL, SQLite, or DuckDB transaction connection.

Adds the optional de.drremote.db:json bundle with JsonQueries and immutable JsonValue snapshots, plus the separate de.drremote-db-json Karaf feature. Existing database modules remain unchanged and require no Jackson dependencies. The caller retains connection and transaction ownership; statements and result sets close on success and failure.

The adapter preserves JDBC numeric values, distinguishes SQL NULL from JSON null when binding, recognizes native JSON/JSONB, and supports explicit parsing of text columns. Coverage includes mixed SQLite runtime types, temporal/nested SQL arrays, binary values, invalid JSON trees, and resource cleanup. English documentation and a buildable OSGi JSON settings client show migrations, readiness, reads, and updates. CI builds both examples.

Validation:

• All 81 tests pass with no skips on Java 17 and 21, including a dedicated PostgreSQL 18 instance and real SQLite/DuckDB drivers.
• All four Karaf feature descriptors resolve successfully.
• Both example bundles compile on Java 17.
• A fresh Karaf 4.4.11 instance runs the JSON client through migration/readiness, insert/update/query, parsed payload, and missing-row checks.
• Independent review findings reproduced and fixed with regression tests; local documentation links and dependency/manifest boundaries checked.