feat(review): inline file uploader instead of redirect home

When a user lands on Review without an upload, show a file uploader
on the page itself and auto-run the analyzer once a file is picked,
rather than bouncing them to the home page with a "Back to home"
button.

Auto-analyze is the right default here: the user is already on the
Review page, so they've implicitly committed to a scan. Stashing the
bytes in the same session-state keys the home page uses keeps the
rest of the flow (encoding picker, gate, tool pages) unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/gui/pages/0_Review.py

@@ -286,15 +286,51 @@ st.caption(
     "the rest before applying."
 )
 
-# Pre-flight: nothing to review without an upload.
+# Pre-flight: if nothing has been uploaded yet, let the user upload
+# directly from this page instead of bouncing them back to the home
+# screen. Once a file is picked, we auto-run the analyzer (the user is
+# already on the Review page — they've implicitly committed to a scan),
+# stash the result, and rerun so the rest of the page picks it up.
 findings: list[Finding] = st.session_state.get("home_findings") or []
 upload_name = st.session_state.get("home_uploaded_name")
 
 if not upload_name:
-    st.warning("No file uploaded. Go back to the home page and upload a CSV or Excel file first.")
-    if st.button("Back to home"):
-        st.switch_page("app.py")
-    st.stop()
+    st.info(
+        "Upload a CSV or Excel file to begin reviewing. The analyzer runs "
+        "locally and your data never leaves this computer."
+    )
+    review_upload = st.file_uploader(
+        "Choose a file",
+        type=["csv", "tsv", "xlsx", "xls"],
+        key="review_upload",
+        help="Drag-and-drop or browse for a CSV, TSV, or Excel file.",
+    )
+    if review_upload is None:
+        st.stop()
+
+    # New file → stash bytes + size + name, drop any stale state, then
+    # run the analyzer. The rerun at the bottom lets the rest of this
+    # page render with the upload in place.
+    same_file = (
+        st.session_state.get("home_uploaded_name") == review_upload.name
+        and st.session_state.get("home_uploaded_size") == review_upload.size
+    )
+    if not same_file:
+        st.session_state["home_uploaded_name"] = review_upload.name
+        st.session_state["home_uploaded_size"] = review_upload.size
+        st.session_state["home_uploaded_bytes"] = review_upload.getvalue()
+        st.session_state.pop("home_findings", None)
+        st.session_state.pop("home_skipped", None)
+        st.session_state.pop("review_decisions", None)
+        st.session_state.pop("normalization_result", None)
+        st.session_state.pop("normalization_for", None)
+        st.session_state.pop("encoding_override", None)
+
+    if st.session_state.get("home_findings") is None:
+        with st.spinner("Analyzing…"):
+            st.session_state["home_findings"] = _run_analysis_with_override(None)
+        st.session_state["home_skipped"] = False
+    st.rerun()
 
 # ---- Encoding picker --------------------------------------------------------
 #

tests/gui/test_workflows.py

@@ -156,16 +156,24 @@ class TestPipelineRunnerWorkflow:
 # ---------------------------------------------------------------------------
 
 class TestReviewWorkflow:
-    """The Review page is the gate-fixer. Without an upload it shows a
-    'go back to home' message. With an upload it runs the analyzer and
-    shows findings."""
+    """The Review page is the gate-fixer. Without an upload it shows
+    its own file uploader so the user can start the flow from this
+    page directly. With an upload it runs the analyzer and shows
+    findings."""
 
-    def test_no_upload_shows_back_to_home(self, app_factory):
+    def test_no_upload_shows_inline_uploader(self, app_factory):
         app = app_factory("0_Review")
         app.run()
         text = collected_text(app)
-        # Page shows ``No file uploaded`` + ``Back to home``.
-        assert "No file uploaded" in text or "uploaded" in text.lower()
+        # Page should invite the user to upload, not redirect home.
+        assert "Upload" in text or "Choose a file" in text, (
+            f"Review page should expose an inline uploader; got:\n{text[:400]}"
+        )
+        # The 'Back to home' button is gone — the page is self-contained now.
+        labels = [b.label for b in app.button]
+        assert not any("Back to home" in lbl for lbl in labels), (
+            f"Back-to-home button should be removed; got buttons: {labels}"
+        )
 
     def test_with_upload_shows_review_content(
         self, app_factory, small_csv_bytes,