Merge pull request 'docs: Desktop Stacker — free app, optional account, slide credit; five engines' (#1133) from docs/stacker-free-copy into main

Reviewed-on: #1133

README.md

@@ -80,8 +80,8 @@ A multi-project .NET 10 solution providing:
 │  │                  │  │   Compose)       │  │                  │          │
 │  └────────┬─────────┘  └────────┬─────────┘  └────────┬─────────┘          │
 │  ┌──────────────────┐  ┌──────────────────┐                                 │
-│  │  Time & Materials│  │  Desktop Stacker │   (Stacker is fully offline —   │
+│  │  Time & Materials│  │  Desktop Stacker │   (Stacker: offline pipeline,   │
-│  │  Android app     │  │  (Rust, offline) │    no backend connection)       │
+│  │  Android app     │  │  (Rust, offline) │    publish needs sign-in)       │
 │  └────────┬─────────┘  └──────────────────┘                                 │
 └───────────┼─────────────────────┼─────────────────────┼─────────────────────┘
             │ HTTPS/WSS           │ HTTPS + WSS          │ WSS (GameServer)
@@ -930,7 +930,7 @@ Note: this repo currently has **no CI** — in-engine test scripts only (`tests/
 
 ## Desktop Stacker (spikersoft-stacker)
 
-A **local, fully offline** focus-stacking application (Zerene/Helicon class) for macro photography — one self-contained executable per OS (macOS / Windows / Linux). It ports the platform's PhotoStack pipeline (artpipe `align.py` + `fusion.py`) to a fast desktop workflow; algorithm parity with the Python implementation is verified by a test harness in the repo.
+A **local, offline-first** focus-stacking application (Zerene/Helicon class) for macro photography — one self-contained executable per OS (macOS / Windows / Linux). It ports the platform's PhotoStack pipeline (artpipe `align.py` + `fusion.py`) to a fast desktop workflow; algorithm parity with the Python implementation is verified by a test harness in the repo.
 
 ### Workflow stages
 
@@ -938,7 +938,7 @@ A **local, fully offline** focus-stacking application (Zerene/Helicon class) for
 1. **Import** — `.ORF` and other RAW/TIFF/JPEG; instant previews from embedded JPEGs; Olympus `FocusStepCount` ordering and duplicate curation.
 2. **Align** — phase-correlation seeding + chained pyramidal ECC-style affine refinement against a reference frame.
 3. **Mass crop** — auto intersection rect of all aligned frames, adjustable on the master; "Crop" bakes warp+crop into every frame so no border replication reaches fusion.
-4. **Stack** — selectable fusion engines: **Laplacian pyramid** and **depth map**.
+4. **Stack** — five fusion engines: **Laplacian pyramid**, **depth map**, **complex wavelet**, **Spiker**, and the content-aware **Patch** engine, validated against a ground-truth harness.
 5. **Touch up** — dual synced previews (source frame | fused result); a soft brush copies source pixels into the result at full 16-bit resolution, with stroke-replay undo.
 6. **Export** — 16-bit TIFF / JPEG + a JSON `.sstack` project sidecar.
 
@@ -946,7 +946,9 @@ A **local, fully offline** focus-stacking application (Zerene/Helicon class) for
 
 A Rust workspace of four crates: `stacker-core` (the pipeline — no UI deps; `rawler` RAW decode, `rustfft`, `rayon`, `memmap2`), `stacker-gpu` (**wgpu** compute kernels from one WGSL codebase targeting Metal/Vulkan/DX12, with a CPU fallback for every kernel), `stacker-camera` (Olympus Wi-Fi CGI protocol + UDP live view + optional BLE wake, plus a mock camera for tests), and `stacker-app` (egui/eframe desktop UI).
 
-**Platform integration: none, by design.** There is no S3 client, no Keycloak, no `api.spikersoft.com` anywhere in the workspace — it shares *algorithms* with the platform's [Photo Stack](#art-studio) lane, not services. Output stays local.
+**Free app, optional account.** Stacker is free — nothing to buy, no registration key, and every stage above works offline without an account. **Account → Sign in with spikersoft.com** (the website's Keycloak SSO session, via a loopback PKCE flow) links the app to a spikersoft.com account, which unlocks **Publish to spikersoft.com** (source frames + finished stack with provenance and Darwin Core identification into the user's gallery, optional blog post, optional public share page at `/p/{token}`) and removes the small `spikersoft.com/stacker` credit that unlinked copies add to exported **share-set slides**. That credit points at the free app page, never at donations, and the finished TIFF / JPEG export never carries it. The public [`/stacker`](https://spikersoft.com/stacker) page lists per-platform installers proxied by `api.spikersoft.com` from the repo's rolling Gitea Release (`latest`).
+
+Beyond publishing, the app shares *algorithms* with the platform's [Photo Stack](#art-studio) lane, not services: no S3 client, and every pipeline stage runs locally.
 
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