webhook through event system, extract data-generators adapter

webhook route now emits WebhookDataReceived event instead of directly
mutating DataProjection and broadcasting. event_handler applies data
and pushes incremental DataUpdate.

clock/static_text generators extracted to data-generators crate behind
DataSourcePort. chrono removed from bootstrap. polling adapters grouped
into Adapters struct.

Cargo.toml

@@ -16,6 +16,7 @@ members = [
     "crates/adapters/media",
     "crates/adapters/auth",
     "crates/adapters/secret-store",
+    "crates/adapters/data-generators",
     "crates/api-types",
     "crates/bootstrap",
     "crates/client-desktop",
@@ -57,5 +58,4 @@ postcard = { version = "1.1", default-features = false, features = ["alloc"] }
 tokio = { version = "1.0", features = ["macros", "rt", "rt-multi-thread", "net", "sync", "time", "io-util"] }
 tower = "0.5"
 reqwest = { version = "0.12", features = ["json"] }
-chrono = "0.4"
-chrono-tz = "0.10"
+data-generators = { path = "crates/adapters/data-generators" }