Add Push/Pull streaming model and TypeScript TCP library

Spec changes (v1.1.0):
- Replace Stream/Sink with Push/Pull type names
- Push<T> = caller→callee, Pull<T> = callee→caller
- Caller allocates ALL stream IDs (both directions)
- Response implicitly closes Pull streams
- Service definitions are from caller's POV
- Callee handlers have types flipped (Push↔Pull)
- Use peer-neutral terminology (caller/callee, not client/server)

New TypeScript library (typescript/tcp/):
- CobsFramed for COBS over TCP
- Connection with Hello exchange and message loop
- Server class for subject testing

Refactored subjects to use new libraries:
- Rust subject uses roam-tcp crate
- TypeScript subject uses @roam/tcp (294 LOC → 40 LOC)

Author: fasterthanlime

Cargo.lock

@@ -12,6 +12,7 @@ members = [
     "rust/roam-shm",
     "rust/roam-codegen",
     "rust/roam-macros",
+    "rust/roam-tcp",
     "rust/subject-rust",
     # New compliance suite
     "spec/spec-proto",
@@ -31,6 +32,7 @@ default-members = [
     "rust/roam-shm",
     "rust/roam-codegen",
     "rust/roam-macros",
+    "rust/roam-tcp",
 ]
 
 [workspace.package]