README: lead with hosted raiw.cc CTA, honest free/paid split

Move the raiw.cc call-to-action above the sponsor ask and drop the
misleading "free web service" framing: visible-watermark and metadata
removal are free, invisible removal runs on paid cloud GPUs. Also point
no-GPU users to the hosted service from the invisible-removal feature
bullet, where the GPU requirement is stated.

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

README.md

@@ -4,6 +4,10 @@ Remove **visible** and **invisible** AI watermarks from images generated by Goog
 
 Strips SynthID, C2PA Content Credentials, EXIF/XMP "Made with AI" labels, and visible sparkle overlays — all in one command.
 
+> ## Try it online: [raiw.cc](https://raiw.cc)
+>
+> No Python, no GPU, no setup. Visible-watermark and metadata removal are **free**. Invisible-watermark removal (SynthID / SDXL regeneration) normally needs a local GPU and ~2 GB of models. On **[raiw.cc](https://raiw.cc)** it runs on cloud GPUs in one click for a small per-image fee.
+
 [![Sponsor](https://img.shields.io/badge/Sponsor-GitHub-db61a2?logo=githubsponsors&logoColor=white)](https://github.com/sponsors/wiltodelta)
 
 If this tool saves you time, consider [sponsoring its development](https://github.com/sponsors/wiltodelta).
@@ -11,7 +15,7 @@ If this tool saves you time, consider [sponsoring its development](https://githu
 ## Features
 
 - **Visible watermark removal** — Gemini / Nano Banana sparkle logo via reverse alpha blending (fast, offline, deterministic)
-- **Invisible watermark removal** — SynthID, StableSignature, TreeRing via diffusion-based regeneration
+- **Invisible watermark removal** — SynthID, StableSignature, TreeRing via diffusion-based regeneration (needs a local GPU, or run it with no setup on [raiw.cc](https://raiw.cc))
 - **AI metadata stripping** — EXIF, PNG text chunks, C2PA provenance manifests (PNG / JPEG / AVIF / HEIF / JPEG-XL), XMP DigitalSourceType
 - **"Made with AI" label removal** — removes the metadata that triggers AI labels on Instagram, Facebook, X (Twitter)
 - **Analog Humanizer** — film grain and chromatic aberration to bypass AI image classifiers
@@ -20,8 +24,6 @@ If this tool saves you time, consider [sponsoring its development](https://githu
 - **Detection** — three-stage NCC watermark detection with confidence scoring
 - **Provenance detection (`identify`)** — aggregate C2PA issuer, IPTC "Made with AI", embedded SD/ComfyUI params, EXIF/XMP generator tags, the SynthID metadata proxy, the visible sparkle, and the open SD/SDXL/FLUX invisible watermark into one origin-platform + watermark-inventory verdict (`--json` for machine output)
 
-> **Try it online** — don't want to install anything? Use [raiw.cc](https://raiw.cc), a free web service powered by this library.
-
 ## Examples
 
 | Before (Watermarked) | After (Cleaned) |