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/pages/7_Multi_File_Merger.py

@@ -14,13 +14,11 @@ if str(_project_root) not in sys.path:
 from src.gui.components import (
     hide_streamlit_chrome,
     require_feature_or_render_upgrade,
-    require_normalization_gate,
 )
 from src.license import FeatureFlag
 
 hide_streamlit_chrome()
 require_feature_or_render_upgrade(FeatureFlag.MULTI_FILE_MERGER)
-require_normalization_gate()
 
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