Run node code on the venv Fluksio was installed into

The workflow this serves: make a venv, install what you work with, then `pip
install fluksio` into the same one. Building a second environment beside it
was exactly wrong — the packages the nodes need are already here, and the
Modules screen was asking for them a second time.

`NODE_VENV=auto` (the default) adopts that venv. It declines in the three
cases where adopting would be wrong: `managed` says otherwise, a managed venv
already exists and may hold packages somebody installed on purpose, or the
engine is not running from a venv at all. The images set `managed`, since the
venv in them holds the app and nothing of anybody else's.

An adopted venv is never written to. `uv pip sync` makes a venv hold exactly
the manifest, so pointed at somebody's own environment it uninstalls their
work and the engine with it — `sync()` refuses outright and `reconcile()`
returns before it can be called at startup, which is where that would have
happened first. The Modules screen lists what is installed and drops its
editor; `pip` is how that environment changes.

`fluksio serve` now names the interpreter node code runs on, which is the
thing a data scientist most needs to know at that moment. `fluksio-worker`
already defaulted `--python` to its own interpreter, so a GPU box works the
same way — that was only ever undocumented.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012ue1tkFWB1bcGy3aWhCKpU

frontend/src/client/schemas.gen.ts

@@ -1521,6 +1521,11 @@ export const ModulesInfoSchema = {
             type: 'boolean',
             title: 'Applied',
             default: false
+        },
+        adopted: {
+            type: 'boolean',
+            title: 'Adopted',
+            default: false
         }
     },
     type: 'object',

frontend/src/client/types.gen.ts

@@ -583,6 +583,7 @@ export type ModulesInfo = {
     requirements?: string;
     packages?: Array<ModulePackage>;
     applied?: boolean;
+    adopted?: boolean;
 };
 
 export type NewPassword = {

frontend/src/routes/_layout/modules.tsx

@@ -62,64 +62,81 @@ function Modules() {
   const requirements = draft ?? stored
   const packages = data?.packages ?? []
   const dirty = requirements !== stored
+  // Fluksio was installed into an environment somebody else made, and node
+  // code runs on it. Installing from here would mean `uv pip sync`, which
+  // holds a venv to exactly one list — and would uninstall their work.
+  const adopted = data?.adopted ?? false
 
   return (
     <div className="grid gap-6">
       <div className="grid gap-1">
         <h1 className="text-2xl">Modules</h1>
         <p className="text-sm text-muted-foreground">
-          The Python packages your function nodes can import. They are installed
-          into an environment of their own, separate from the engine's, so a
-          version you pin here is the one your code gets. The list is kept with
-          your flows, so a rebuilt deployment installs the same set again.
+          {adopted
+            ? "The Python packages your function nodes can import. Fluksio was installed into an environment you already had, so that is the one your nodes run on — and it is yours to change, with pip or uv rather than from here."
+            : "The Python packages your function nodes can import. They are installed into an environment of their own, separate from the engine's, so a version you pin here is the one your code gets. The list is kept with your flows, so a rebuilt deployment installs the same set again."}
         </p>
       </div>
 
-      <section className="grid gap-3">
-        <h2 className={SECTION}>Requirements</h2>
-        <textarea
-          className="min-h-[160px] w-full rounded-md border border-border bg-card p-3 font-mono text-sm shadow-e1 outline-none focus-visible:border-primary"
-          spellCheck={false}
-          aria-label="Requirements"
-          data-testid="requirements"
-          placeholder={"requests==2.32.3\npandas>=2.2"}
-          value={requirements}
-          onChange={(event) => setDraft(event.target.value)}
-        />
-        <div className="flex items-center gap-3">
-          <Button
-            disabled={apply.isPending}
-            data-testid="apply-modules"
-            onClick={() => apply.mutate(requirements)}
-          >
-            <Package />
-            {apply.isPending ? "Installing" : "Apply"}
-          </Button>
-          <span className="text-sm text-muted-foreground">
-            {dirty
-              ? "Not applied yet."
-              : data?.applied
-                ? "Installed and in step."
-                : "What is installed does not match this list."}
-          </span>
-        </div>
-        {output ? (
-          <pre
-            className="max-h-64 overflow-auto rounded-md border border-border bg-card p-3 font-mono text-xs shadow-e1"
-            data-testid="modules-output"
-          >
-            {output}
-          </pre>
-        ) : null}
-      </section>
+      {adopted ? null : (
+        <section className="grid gap-3">
+          <h2 className={SECTION}>Requirements</h2>
+          <textarea
+            className="min-h-[160px] w-full rounded-md border border-border bg-card p-3 font-mono text-sm shadow-e1 outline-none focus-visible:border-primary"
+            spellCheck={false}
+            aria-label="Requirements"
+            data-testid="requirements"
+            placeholder={"requests==2.32.3\npandas>=2.2"}
+            value={requirements}
+            onChange={(event) => setDraft(event.target.value)}
+          />
+          <div className="flex items-center gap-3">
+            <Button
+              disabled={apply.isPending}
+              data-testid="apply-modules"
+              onClick={() => apply.mutate(requirements)}
+            >
+              <Package />
+              {apply.isPending ? "Installing" : "Apply"}
+            </Button>
+            <span className="text-sm text-muted-foreground">
+              {dirty
+                ? "Not applied yet."
+                : data?.applied
+                  ? "Installed and in step."
+                  : "What is installed does not match this list."}
+            </span>
+          </div>
+          {output ? (
+            <pre
+              className="max-h-64 overflow-auto rounded-md border border-border bg-card p-3 font-mono text-xs shadow-e1"
+              data-testid="modules-output"
+            >
+              {output}
+            </pre>
+          ) : null}
+        </section>
+      )}
 
       <section className="grid gap-3">
         <h2 className={SECTION}>Installed</h2>
-        <p className="text-sm text-muted-foreground">
+        <p className="text-sm text-muted-foreground" data-testid="modules-venv">
           {data
             ? `Python ${data.python_version || "unknown"} at ${data.venv_path}`
             : "Reading the environment…"}
         </p>
+        {adopted ? (
+          <p
+            className="text-sm text-muted-foreground"
+            data-testid="modules-adopted"
+          >
+            Adopted — this is the environment Fluksio itself is installed in.
+            Add a package the way you added the rest:{" "}
+            <span className="font-mono">pip install …</span>, then sync or
+            restart so the workers pick it up. For a venv the engine owns
+            instead, set <span className="font-mono">NODE_VENV=managed</span>.
+          </p>
+        ) : null}
         {packages.length === 0 ? (
           <p className="text-sm text-muted-foreground">
             Nothing installed yet — node code has the standard library.