🔖 Add obipipeline parallel pipeline library

- Introduce `obipipline` crate with multi-threaded data pipeline architecture
- Implement core types: SourceFn, SharedFun (Arc), SinkFN with biased scheduler and crossbeam channels
- Add macros: `make_source!`, `transform!/fallible`/sink!, and high-level DSL macro
- Replace old wrapper/error modules with unified scheduler module (renamed types, improved error variants)

- Update workspace: add `obipipeline` member to Cargo.toml and lockfile  
- Document pipeline in docmd/implementation with full architecture, error handling & example
- Refactor sandbox_pipeline.rs to use new DSL instead of manual channel wiring

src/Cargo.lock

@@ -692,6 +692,13 @@ dependencies = [
  "criterion2",
 ]
 
+[[package]]
+name = "obipipeline"
+version = "0.1.0"
+dependencies = [
+ "crossbeam-channel",
+]
+
 [[package]]
 name = "obiread"
 version = "0.1.0"