feedkit: ergonomics pass (shared logger, route compiler, param helpers)

- Add logging.Logf as the canonical printf-style logger type used across feedkit.
  - Update scheduler and dispatch to alias their Logger types to logging.Logf.
  - Eliminates type-mismatch friction when wiring one log function through the system.

- Add dispatch.CompileRoutes(*config.Config) ([]dispatch.Route, error)
  - Compiles config routes into dispatch routes with event.ParseKind normalization.
  - If routes: is omitted, defaults to “all sinks receive all kinds”.

- Expand config param helpers for both SourceConfig and SinkConfig
  - Add ParamBool/ParamInt/ParamDuration/ParamStringSlice (+ Default variants).
  - Supports common YAML-decoded types (bool/int/float/string, []any, etc.)
  - Keeps driver code cleaner and reduces repeated type assertions.

- Fix Postgres sink validation error prefix ("postgres sink", not "rabbitmq sink").

config/config.go

@@ -128,12 +128,3 @@ func (d *Duration) UnmarshalYAML(value *yaml.Node) error {
 	// Anything else: reject.
 	return fmt.Errorf("duration must be a string like 15m or an integer minutes, got tag %s", value.Tag)
 }
-
-func isAllDigits(s string) bool {
-	for _, r := range s {
-		if r < '0' || r > '9' {
-			return false
-		}
-	}
-	return len(s) > 0
-}