refactor(gui): drop Review page + normalization gate

Home is now the only entry point: the "Run analysis" button on the
upload section IS the review step (findings render inline via
render_findings_panel). Tool pages no longer gate on a passed
normalization — running the analyzer is sufficient context.

Removed:
- src/gui/pages/0_Review.py
- src/gui/components/gate.py (re-export seam)
- require_normalization_gate() in src/gui/components/_legacy.py
- "review" section enum in tools_registry.py
- Data Review entry in app.py navigation
- require_normalization_gate() calls + imports in all nine tool pages
- tests/gui/test_gate.py (whole file)
- TestReviewWorkflow in tests/gui/test_workflows.py
- 0_Review entry in tests/gui/test_smoke.py PAGE_SLUGS
- stash_upload's normalization_result+normalization_for stashing
- stash_upload_without_gate (was the gate's negative-path helper)

2017 tests pass (16 retired with the gate flow).

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

src/gui/app.py

@@ -75,7 +75,7 @@ def _home_page() -> None:
     # Group tool cards by sidebar section so the home grid mirrors the
     # left-nav layout — same vocabulary, same ordering.
     sections: list[tuple[str, list]] = []
-    for section in ("review", "cleaners", "transformations", "automations"):
+    for section in ("cleaners", "transformations", "automations"):
         tools = [tool for tool in TOOLS if tool.section == section]
         if not tools:
             continue
@@ -151,7 +151,6 @@ def _page_for(tool_id: str, *, page_slug: str, icon: str, title: str) -> "st.Pag
 
 def _build_navigation() -> dict[str, list]:
     by_section: dict[str, list] = {
-        "review": [],
         "cleaners": [],
         "transformations": [],
         "automations": [],
@@ -166,16 +165,6 @@ def _build_navigation() -> dict[str, list]:
             )
         )
 
-    # The Review gate has no entry in the registry (it isn't a "tool")
-    # so register it by hand at the top of its section.
-    review_page = st.Page(
-        "pages/0_Review.py",
-        title=_t("nav.review_page_title") or "Review",
-        icon="🛡️",
-        url_path="review",
-    )
-    by_section["review"].insert(0, review_page)
-
     home = st.Page(
         _home_page,
         title=_t("nav.home_page_title") or "Home",
@@ -199,7 +188,6 @@ def _build_navigation() -> dict[str, list]:
     account_header = _t("nav.section_account") or "Account"
     return {
         "": [home],
-        section_label("review"): by_section["review"],
         section_label("cleaners"): by_section["cleaners"],
         section_label("transformations"): by_section["transformations"],
         section_label("automations"): by_section["automations"],