fix(home,close): tool-link preserves file context + drop close-page explanation

(1) ``[Tool] →`` action links inside per-file finding rows now
preserve the file that the card belongs to. Previously the home page
re-set ``home_uploaded_*`` to the FIRST imported file on every rerun
— so when a user with multiple imports clicked
``Clean Text →`` on file_B's findings card, the tool page loaded
file_A. The click handler in ``_render_finding_row_v2`` now looks
the file up in ``home_uploads`` by the findings-card filename and
writes ``home_uploaded_name / size / bytes`` BEFORE
``st.switch_page``, so the tool's ``pickup_or_upload`` reads the
right context.

The filename threads through ``render_findings_panel(..., header=)``
→ ``_render_finding_row_v2(..., filename=)``; ``header`` is already
the filename today, so no call-site change needed.

(2) Close screen "explanation" removed. The long browser-restriction
hint paragraph (``quit.close_hint``: "Browsers don't let JavaScript
close a tab you opened yourself …") is gone from the farewell overlay
— the auto-dismiss path lands the user on about:blank within ~1.5s
of the close click, so the explanation never had a chance to be
useful. ``autoDismiss`` simplified to "try close, else redirect"
without the hint-surface step. The i18n key is retained as a no-op
in case the hint comes back.

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

src/gui/components/_legacy.py

@@ -1297,9 +1297,6 @@ _FAREWELL_SCRIPT_TEMPLATE = """
         '<h1 style="margin:0 0 8px 0;font-weight:600;letter-spacing:-0.01em;">' +
         '__TITLE__</h1>' +
         '<p style="opacity:0.7;margin:0;">__SUBTITLE__</p>' +
-        '<p id="datatools-close-hint" style="' +
-        'display:none;font-size:13px;opacity:0.6;margin:14px 0 0 0;">' +
-        '__CLOSE_HINT__</p>' +
         '</div>';
       return overlay;
     }
@@ -1328,20 +1325,19 @@ _FAREWELL_SCRIPT_TEMPLATE = """
       try { win.location.replace('about:blank'); } catch (e) {}
     }
     function autoDismiss(doc, win) {
-      // Try the programmatic close first — succeeds in Chrome/Edge
+      // Try programmatic close first — succeeds in Chrome/Edge
-      // --app windows. If it fails (regular browser tab), surface the
+      // ``--app`` windows. If it fails (regular browser tab),
-      // hint and auto-redirect to about:blank so the user lands on a
+      // auto-redirect to about:blank so the user lands on a clean
-      // clean page instead of the frozen farewell overlay. The "Close
+      // page instead of the frozen farewell overlay. The "Close this
-      // this window" button used to drive the same flow on click; we
+      // window" button + the long browser-restriction hint paragraph
-      // dropped that affordance per UX request, so this auto-timer is
+      // both used to drive / explain this flow; we dropped both per
-      // the only path on regular tabs.
+      // UX request, so this auto-timer is the only path on regular
+      // tabs.
       var standalone = isStandalone(win);
       if (tryClose(win)) return;
-      var hint = doc.getElementById('datatools-close-hint');
-      if (hint) hint.style.display = 'block';
       setTimeout(function () {
         if (!win.closed) fallbackToBlank(win);
-      }, standalone ? 400 : 2500);
+      }, standalone ? 400 : 1500);
     }
     try {
       var doc = window.top.document;
@@ -1383,8 +1379,6 @@ def _farewell_script() -> str:
         _FAREWELL_SCRIPT_TEMPLATE
         .replace("__TITLE__", _js_html_safe(_t("quit.farewell_title")))
         .replace("__SUBTITLE__", _js_html_safe(_t("quit.farewell_subtitle")))
-        .replace("__CLOSE_BTN__", _js_html_safe(_t("quit.close_window_button")))
-        .replace("__CLOSE_HINT__", _js_html_safe(_t("quit.close_hint")))
     )
 
 
@@ -2960,10 +2954,12 @@ def render_findings_panel(
     )
 
     for i, f in sorted_findings:
-        _render_finding_row_v2(f, row_key=f"{ns}_{i}")
+        _render_finding_row_v2(
+            f, row_key=f"{ns}_{i}", filename=header,
+        )
 
 
-def _render_finding_row_v2(f, *, row_key: str) -> None:
+def _render_finding_row_v2(f, *, row_key: str, filename: str = "") -> None:
     """One row inside the per-file findings card.
 
     Layout: severity chip (col 1) · title + meta (col 2) · "Open Tool"
@@ -3025,6 +3021,18 @@ def _render_finding_row_v2(f, *, row_key: str) -> None:
             type="tertiary",
             width="content",
         ):
+            # Set the active file to the one this finding came from
+            # BEFORE switching pages — otherwise the tool page's
+            # ``pickup_or_upload`` reads the home page's "default to
+            # first imported file" state, losing the context of the
+            # card the user clicked. ``filename`` is the per-file
+            # findings group header.
+            home_uploads = st.session_state.get("home_uploads", {})
+            meta = home_uploads.get(filename) if filename else None
+            if meta:
+                st.session_state["home_uploaded_name"] = filename
+                st.session_state["home_uploaded_size"] = meta["size"]
+                st.session_state["home_uploaded_bytes"] = meta["bytes"]
             st.switch_page(page_slug)
 
     body_html = f'<p class="dt-finding-title">{title_html}</p>'