refactor: put the dry-run and quiet checks on Ctx

src/ctx.rs

@@ -1,6 +1,22 @@
+use crate::cmd::Compose;
+use crate::fsops::Fs;
+
 // how ahab was invoked, handed to everything that runs commands or writes files
 pub struct Ctx {
     pub verbose: bool,
     pub dry_run: bool,
     pub quiet: bool,
 }
+
+impl Ctx {
+    // the two things these flags actually decide, asked for by name rather than
+    // read field by field wherever they are needed: a dry run writes nothing,
+    // and --quiet stops compose narrating
+    pub fn fs(&self) -> Fs<'_> {
+        Fs::new(self)
+    }
+
+    pub fn compose(&self) -> Compose<'_> {
+        Compose::new(self)
+    }
+}