SCL adds cursor-based streaming to Sakura so clients can consume DRL query results incrementally in bounded batches rather than all at once. Three statements: Begin, Fetch, and Close. `open`, `advance`, and `release` cursors backed by a session registry that suspends the generator between calls. SCL is just an optional consumption layer above the existing algebra.

* separation and functor for sublanguages

* add coq experiment for termination

* fix tests with envelopes

* add timestamp and print responses to server on terminal

* remove coq experiment for trivial cases and rework gate

* refactor nesting with let*

* remove non-envelope sublang support and tests on server

* manip_err duplication purge and better format as s-expr

* abstract storage with dispatch for sublanguages

* dead code and minor refactor due to old non-envelope parsing on subl

* refactor server to use proper dml alg error and wire ephem relations

* remove (schema)

* change .gitignore to blacklist folders