feat(runtime): replace tokio+reqwest with asupersync async runtime

- Add HTTP adapter layer (src/http.rs) wrapping asupersync h1 client
- Migrate gitlab client, graphql, and ollama to HTTP adapter
- Swap entrypoint from #[tokio::main] to RuntimeBuilder::new().block_on()
- Rewrite signal handler for asupersync (RuntimeHandle::spawn + ctrl_c())
- Migrate rate limiter sleeps to asupersync::time::sleep(wall_now(), d)
- Add asupersync-native HTTP integration tests
- Convert timeline_seed_tests to RuntimeBuilder pattern

Phases 1-3 of asupersync migration (atomic: code won't compile without all pieces).

Cargo.toml

@@ -29,15 +29,11 @@ lipgloss = { package = "charmed-lipgloss", version = "0.2", default-features = f
 open = "5"
 
 # HTTP
-reqwest = { version = "0.12", features = ["json"] }
-tokio = { version = "1", features = ["rt-multi-thread", "macros", "time", "signal"] }
-
-# Async runtime (asupersync migration candidate)
-asupersync = { version = "0.2", features = ["tls", "tls-native-roots", "proc-macros"] }
+asupersync = { version = "0.2", features = ["tls", "tls-native-roots"] }
 
 # Async streaming for pagination
 async-stream = "0.3"
-futures = { version = "0.3", default-features = false, features = ["alloc"] }
+futures = { version = "0.3", default-features = false, features = ["alloc", "async-await"] }
 
 # Utilities
 thiserror = "2"
@@ -63,6 +59,7 @@ tracing-appender = "0.2"
 
 [dev-dependencies]
 tempfile = "3"
+tokio = { version = "1", features = ["rt", "rt-multi-thread", "macros"] }
 wiremock = "0.6"
 
 [profile.release]