fix: CLJS watch mode missing todomvc from cljs_deps.js

Two issues caused "Loading from local store..." after tmux restart:

1. Watch path only included `src/`, so `example/todomvc/` sources
   weren't compiled on the watcher's initial build, leaving
   pocketbook.todomvc out of cljs_deps.js.
   Fix: `-w "src:example/todomvc"`

2. Stale output dir from previous builds caused incremental compile
   to skip regenerating cljs_deps.js.
   Fix: `cljs:clean` task (deletes js output) runs before `cljs:watch`.

bb.edn

@@ -5,7 +5,11 @@
   cljs {:doc "Compile ClojureScript (one-shot)"
         :task (shell "clj" "-M:cljs")}
 
+  cljs:clean {:doc "Remove compiled CLJS output"
+              :task (babashka.fs/delete-tree "example/todomvc/js")}
+
   cljs:watch {:doc "Compile ClojureScript (watch mode)"
+              :depends [cljs:clean]
               :task (shell "clj" "-M:cljs-dev")}
 
   test {:doc "Run all server tests"