deps phases 3-4: uberscript bundling + conformance harness

Phase 3 — bundling. `jolt uberscript OUT -m NS` requires NS, uses the loader's
recorded load order (a dep finishes loading before its requirer, so it's
topological) to concatenate the used namespaces into one .clj that runs on a
plain jolt with no deps/jpm. `jolt-deps uberscript` resolves first. The loader
records loaded file paths when ctx env has :loaded-files.

Phase 4 — conformance. deps-conformance-test resolves real pure-cljc git libs
and reports load/run status, gated behind JOLT_CONFORMANCE so CI stays offline.
First run: medley works; cuerdas hits a reader gap (filed); stuartsierra/
dependency uses Long/MAX_VALUE (JVM interop, out of scope).

Tests: uberscript-test, deps-conformance-test (skips without the flag).

test/integration/uberscript-test.janet

@@ -0,0 +1,51 @@
+# `jolt uberscript` bundles a namespace and everything it requires into one .clj
+# that runs on a plain jolt with no JOLT_PATH / deps. Runs from source.
+
+(defn- run [env-jolt-path & args]
+  (if env-jolt-path (os/setenv "JOLT_PATH" env-jolt-path) (os/setenv "JOLT_PATH" nil))
+  (def p (os/spawn ["janet" "src/jolt/main.janet" ;args] :p {:out :pipe :err :pipe}))
+  (def out (:read (p :out) :all))
+  (os/proc-wait p)
+  (string (or out "")))
+
+(defn- mkdirs [p]
+  (var acc nil)
+  (each seg (filter |(not= "" $) (string/split "/" p))
+    (set acc (if (nil? acc) (if (string/has-prefix? "/" p) (string "/" seg) seg) (string acc "/" seg)))
+    (unless (os/stat acc) (os/mkdir acc))))
+(defn- rmrf [p]
+  (when (os/stat p)
+    (if (= :directory (os/stat p :mode))
+      (do (each e (os/dir p) (rmrf (string p "/" e))) (os/rmdir p))
+      (os/rm p))))
+
+(def base (string (or (os/getenv "TMPDIR") "/tmp") "/jolt-uber-" (os/time)))
+(rmrf base)
+(mkdirs (string base "/proj/src/app"))
+(mkdirs (string base "/lib/src/greet"))
+(spit (string base "/lib/src/greet/core.clj")
+      "(ns greet.core)\n(defn hello [n] (str \"Hello, \" n \"!\"))\n")
+(spit (string base "/proj/src/app/core.clj")
+      "(ns app.core (:require [greet.core :as g]))\n(defn -main [& args] (println (g/hello (or (first args) \"world\"))))\n")
+
+(var fails 0)
+(defn check [label got pred]
+  (if (pred got) (print "  ok   " label)
+    (do (++ fails) (printf "  FAIL %s: got %q" label got))))
+(defn- has [s] (fn [x] (string/find s x)))
+
+(def roots (string base "/proj/src:" base "/lib/src"))
+(def out (string base "/out.clj"))
+
+# build the uberscript with the dep roots on JOLT_PATH
+(run roots "uberscript" out "-m" "app.core")
+(check "uberscript written" (if (os/stat out) "yes" "no") (has "yes"))
+(check "bundles the dep ns" (slurp out) (has "(ns greet.core)"))
+
+# run it standalone: no JOLT_PATH, so it only works if the dep was inlined
+(check "runs standalone" (run nil out "Bob") (has "Hello, Bob!"))
+
+(rmrf base)
+(if (> fails 0)
+  (error (string "uberscript-test: " fails " failing check(s)"))
+  (print "\nAll uberscript tests passed!"))