feat: frame output for copy-to-LLM use with one-click copy button

Clarify the core flow: extract locally, copy the redacted output, paste into
any LLM with no raw PII exposed.

- app.py: add a one-click copy button on the safe output (version-safe via
_COPY, since show_copy_button exists in Gradio 5.x but not 6.x); relabel
outputs ("Safe output — copy into your LLM" / "Extracted fields — stays
local, never sent"); reword the header to describe the copy-to-LLM flow.

Co-authored-by: OpenAI Codex <codex@openai.com>

app.py

@@ -21,6 +21,16 @@ from redac import (
 )
 from redac.detect import gliner_available
 
+import inspect
+
+# show_copy_button exists in Gradio 5.x; in 6.x copying is the default and the
+# kwarg was removed. Pass it only when supported so the app runs on both.
+_COPY = (
+    {"show_copy_button": True}
+    if "show_copy_button" in inspect.signature(gr.Textbox.__init__).parameters
+    else {}
+)
+
 _NER_NOTE = (
     "" if gliner_available()
     else "\n\n> ⚠️ GLiNER not installed: running **regex-only** (structured "
@@ -64,8 +74,10 @@ def do_rehydrate(redacted_text, mapping):
 with gr.Blocks(title="Redac", theme=gr.themes.Soft()) as demo:
     gr.Markdown(
         "# 🖍️ Redac\n"
-        "**A local privacy gateway.** Detect and redact PII *before* it reaches "
-        "a downstream model. Reversible: the mapping stays local." + _NER_NOTE
+        "**A local privacy gateway.** Upload a document or paste text, Redac "
+        "extracts and redacts the PII *locally*, and you copy the safe output to "
+        "use with any LLM. Raw values never leave: the mapping stays local so you "
+        "can rehydrate answers yourself." + _NER_NOTE
     )
 
     with gr.Tabs():
@@ -87,7 +99,11 @@ with gr.Blocks(title="Redac", theme=gr.themes.Soft()) as demo:
                     t_thr = gr.Slider(0.1, 0.9, value=0.45, step=0.05, label="Threshold")
                     t_btn = gr.Button("Redact", variant="primary")
                 with gr.Column():
-                    t_out = gr.Textbox(label="Redacted (safe to send downstream)", lines=10)
+                    t_out = gr.Textbox(
+                        label="✅ Safe output — copy this into your LLM (no raw PII)",
+                        lines=10,
+                        **_COPY,
+                    )
                     t_sum = gr.Markdown()
                     t_tab = gr.Dataframe(
                         headers=["type", "value", "score", "source"],
@@ -117,8 +133,15 @@ with gr.Blocks(title="Redac", theme=gr.themes.Soft()) as demo:
                     i_thr = gr.Slider(0.1, 0.9, value=0.45, step=0.05, label="Threshold")
                     i_btn = gr.Button("Extract & redact", variant="primary")
                 with gr.Column():
-                    i_extracted = gr.Textbox(label="Extracted fields (raw)", lines=8)
-                    i_out = gr.Textbox(label="Redacted (safe to send downstream)", lines=8)
+                    i_extracted = gr.Textbox(
+                        label="🔒 Extracted fields (raw — stays local, never sent)",
+                        lines=8,
+                    )
+                    i_out = gr.Textbox(
+                        label="✅ Safe output — copy this into your LLM (no raw PII)",
+                        lines=8,
+                        **_COPY,
+                    )
                     i_sum = gr.Markdown()
                     i_tab = gr.Dataframe(
                         headers=["type", "value", "score", "source"],