feat(invisible): protect text automatically by default (#21)

Mirror protect_faces: protect_text defaults to True in invisible_engine and
watermark_remover, so the SDXL pipeline detects text per image and switches to
Differential Diffusion only when glyphs are found. Text-free inputs fall back to
plain img2img with no differential-pipeline load, so the autonomy is free. The
CLI now exposes a single off-switch --no-protect-text instead of the positive
flag, keeping the interface minimal.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/remove_ai_watermarks/cli.py

@@ -461,10 +461,10 @@ def cmd_erase(
     help="Cap long side (px) before diffusion; 0 = native (best quality, like raiw.cc). Raise only on GPU/MPS OOM.",
 )
 @click.option(
-    "--protect-text",
+    "--no-protect-text",
     is_flag=True,
     default=False,
-    help="Preserve detected text (incl. CJK) via Differential Diffusion. SDXL default pipeline only.",
+    help="Disable automatic text protection (text/CJK is preserved by default on the SDXL pipeline).",
 )
 @click.pass_context
 def cmd_invisible(
@@ -479,7 +479,7 @@ def cmd_invisible(
     hf_token: str | None,
     humanize: float,
     max_resolution: int,
-    protect_text: bool,
+    no_protect_text: bool,
 ) -> None:
     """Remove invisible AI watermarks (SynthID, StableSignature, TreeRing).
 
@@ -526,7 +526,7 @@ def cmd_invisible(
         guidance_scale=None,
         seed=seed,
         humanize=humanize,
-        protect_text=protect_text,
+        protect_text=not no_protect_text,
         max_resolution=max_resolution,
     )
     elapsed = time.monotonic() - t0
@@ -680,10 +680,10 @@ def cmd_identify(ctx: click.Context, source: Path, no_visible: bool, as_json: bo
     help="Cap long side (px) before diffusion; 0 = native (best quality, like raiw.cc). Raise only on GPU/MPS OOM.",
 )
 @click.option(
-    "--protect-text",
+    "--no-protect-text",
     is_flag=True,
     default=False,
-    help="Preserve detected text (incl. CJK) via Differential Diffusion. SDXL default pipeline only.",
+    help="Disable automatic text protection (text/CJK is preserved by default on the SDXL pipeline).",
 )
 @click.pass_context
 def cmd_all(
@@ -701,7 +701,7 @@ def cmd_all(
     hf_token: str | None,
     humanize: float,
     max_resolution: int,
-    protect_text: bool,
+    no_protect_text: bool,
 ) -> None:
     """Remove ALL watermarks: visible + invisible + metadata.
 
@@ -793,7 +793,7 @@ def cmd_all(
                 num_inference_steps=steps,
                 seed=seed,
                 humanize=humanize,
-                protect_text=protect_text,
+                protect_text=not no_protect_text,
                 max_resolution=max_resolution,
             )
             console.print("    [green]✓[/] Invisible watermark removed")