docs(readme): reorganise for clarity + beginner on-ramps, surface the FFmpeg upstreaming

Top-to-bottom readable without losing a newcomer, navigable in one click:
- one-sentence plain-English opener + clickable table of contents
- New here? three-words glossary (codec / decode-demux / reverse-engineering)
- plain intro line on each major section
- new 'Where it stands now': the DS2 + DSS-SP fixes submitted to ffmpeg-devel
  (in review), the public spec, the PRONOM preservation submission
- FFmpeg 'patches in review' badge; chapter 13 added to the trail; ffmpeg-upstream
  bullet updated from 'staged' to 'submitted'
Keeps the thriller hook, 30s quickstart, before/after diagram, prod numbers, credits.

Author: Guillain-RDCDE

README.md

@@ -4,7 +4,12 @@
 > and now **Grundig DSS** — on any Linux box. No Windows, no GUI, no commercial
 > software. A production recipe *and* the reverse-engineering trail behind it. 🔓
 
-[![CI](https://github.com/Guillain-RDCDE/DS2-Anywhere/actions/workflows/ci.yml/badge.svg)](https://github.com/Guillain-RDCDE/DS2-Anywhere/actions/workflows/ci.yml) [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE) [![Latest release](https://img.shields.io/github/v/release/Guillain-RDCDE/DS2-Anywhere)](https://github.com/Guillain-RDCDE/DS2-Anywhere/releases) ![Status](https://img.shields.io/badge/status-production-green) ![Platform](https://img.shields.io/badge/platform-linux-blue)
+[![CI](https://github.com/Guillain-RDCDE/DS2-Anywhere/actions/workflows/ci.yml/badge.svg)](https://github.com/Guillain-RDCDE/DS2-Anywhere/actions/workflows/ci.yml) [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE) [![Latest release](https://img.shields.io/github/v/release/Guillain-RDCDE/DS2-Anywhere)](https://github.com/Guillain-RDCDE/DS2-Anywhere/releases) ![Status](https://img.shields.io/badge/status-production-green) ![FFmpeg](https://img.shields.io/badge/FFmpeg-patches%20in%20review-orange) ![Platform](https://img.shields.io/badge/platform-linux-blue)
+
+**In one sentence:** doctors, lawyers and police dictate into small voice recorders;
+the file format those recorders produce was kept secret for thirty years; this project
+opens it on any Linux machine — and gives the fix back to the open-source tools everyone
+uses.
 
 ---
 
@@ -19,12 +24,34 @@ from its DLLs.
 
 All of it is in here: the working code, and exactly how it was done.
 
+## Contents
+
+- [New here? Three words in plain English](#new-here-three-words-in-plain-english)
+- [Pick your way in](#pick-your-way-in) — four doors, choose your depth
+- [Try it in 30 seconds](#try-it-in-30-seconds)
+- [What it does, in one picture](#what-it-does-in-one-picture)
+- [The technical trail](#the-technical-trail) — the story, chapter by chapter
+- [Where it stands now](#where-it-stands-now) — giving it back to FFmpeg & preservation
+- [Real-world numbers](#real-world-numbers)
+- [What's in this repo](#whats-in-this-repo)
+- [Credits](#credits--proper-order) · [License](#license)
+
+## New here? Three words in plain English
+
+You don't need any audio or programming background to follow this repo. Three terms cover most of it:
+
+- **Codec** — the secret "recipe" that squeezes a voice recording into a tiny file, and rebuilds it on playback. Without the recipe, the file is just unreadable noise.
+- **Decode** (and **demux**) — turning that tiny file back into sound. *Demux* is the first step (split the file into the right little chunks, called *frames*); *decode* is the second (turn frames into audio). Most of our hardest bugs were in the *demux* step — getting the chunks lined up.
+- **Reverse-engineering** — working out the secret recipe yourself, by careful observation, because the manufacturer never published it.
+
+That's it. Everything below builds gently from these.
+
 ## Pick your way in
 
 | | |
 |---|---|
 | 📖 **Read it like a thriller** | **[The Story →](docs/THE-STORY.md)** — no code, ~10 minutes. A locked format, a relay of strangers, a bug that turned out to be a human being, and a German lawyer's drawer. It really happened, and every twist links to the chapter that proves it. |
-| 🔧 **Follow the technical trail** | **[Go deeper ↓](#go-deeper-the-technical-trail)** — from "what even *is* a `.ds2` file" up to running a closed-source decoder under a debugger. Built to be readable if you've never reverse-engineered anything. |
+| 🔧 **Follow the technical trail** | **[Go deeper ↓](#the-technical-trail)** — from "what even *is* a `.ds2` file" up to running a closed-source decoder under a debugger. Built to be readable if you've never reverse-engineered anything. |
 | 🌐 **Decode one right now** | **[Open the in-browser decoder →](https://guillain-rdcde.github.io/DS2-Anywhere/)** — drop a `.ds2`/`.dss` (Olympus, Grundig, even encrypted) and get audio back. Nothing uploaded, nothing installed. |
 | 🛠 **Run it yourself** | **[30 seconds ↓](#try-it-in-30-seconds)** — drop a file in, get an MP3 out. |
 
@@ -51,6 +78,8 @@ Production install (config + cron + systemd + web UI): `sudo ./src/bin/install.s
 
 ## What it does, in one picture
 
+The whole point in one diagram: a Windows VM running commercial software, replaced by a small local binary.
+
 ```
                    BEFORE                                            AFTER
 
@@ -72,18 +101,15 @@ A Windows VM with commercial software in the loop, replaced by a bash wrapper, a
 
 ---
 
-## Go deeper: the technical trail
-
-**New to any of this?** A `.dss`/`.ds2` file is a voice recording squeezed *tiny* by
-a secret algorithm (a "codec"). "Decoding" it means rebuilding the original sound
-from those bytes — and to do that you need the algorithm, which the manufacturers
-never published. The whole trail below is the story of getting it anyway. You don't
-need a background in audio or reverse-engineering to follow it; each chapter starts
-from the ground.
+## The technical trail
 
-Climb at your own pace:
+**Start from zero.** A `.dss`/`.ds2` file is a voice recording squeezed *tiny* by a
+secret algorithm (see [the three words above](#new-here-three-words-in-plain-english)).
+"Decoding" it means rebuilding the original sound — and to do that you need the
+algorithm, which the manufacturers never published. The chapters below are the story of
+getting it anyway. Each one starts from the ground; you can stop at any rung.
 
-1. **[The ten-year lock](docs/01-reverse-engineering.md)** — what a DS2 file is, why it
+1. **[The thirty-year lock](docs/01-reverse-engineering.md)** — what a DS2 file is, why it
    resisted, and how Kieran Hirpara reverse-engineered the codec from the Olympus DLLs
    (the genius part — not ours).
 2. **[Putting it in production](docs/02-integration.md)** — turning a decoder into a
@@ -94,23 +120,43 @@ Climb at your own pace:
 4. **[Cracking the re-sync block](docs/07-cracking-the-resync-block.md)** — the sequel:
    we ran the closed-source Olympus decoder *inside a debugger we built from its own
    DLLs*, and read the format's last undocumented rule straight off the silicon.
-5. **[The bug that wasn't](docs/10-the-reckoning-the-bug-that-wasnt.md)** — the twist,
+5. **[The re-sync block, again — and into FFmpeg](docs/13-the-sp-resync-block.md)** — the
+   same trick a second time, on Olympus's *other* format (DSS SP). We re-hosted the
+   vendor's decoder, read the rule off the live parser, fixed it in one branch — and this
+   time **sent the fix to FFmpeg itself** (see [where it stands](#where-it-stands-now)).
+6. **[The bug that wasn't](docs/10-the-reckoning-the-bug-that-wasnt.md)** — the twist,
    and the chapter we're proudest of. A rigorous case for a "last bug" ([the research
    paper](docs/09-the-resync-excitation-anomaly.md)), then *overturned* — there was no
    bug; it was a person stepping away from the mic. How careful work can be confidently
    wrong, and how to catch it.
-6. **[Cracking the Grundig SP codec](docs/12-cracking-the-grundig-sp-codec.md)** — the
+7. **[Cracking the Grundig SP codec](docs/12-cracking-the-grundig-sp-codec.md)** — the
    finale. The Grundig grandfather format that *nobody* decoded — not us, not FFmpeg,
    not even Olympus's own software. We extracted Grundig's decoder, ran it under a
    debugger, patched out the instruction it used to delete its own evidence, and
-   rebuilt the codec **bit-exact**. Now a [native Python decoder](grundig/), an
-   [FFmpeg patch](ffmpeg-upstream/patches/avcodec-grundig_sp-decoder.patch), and a PR
-   to the upstream codec.
+   rebuilt the codec **bit-exact**. Now a [native Python decoder](grundig/) and an
+   [FFmpeg patch](ffmpeg-upstream/patches/avcodec-grundig_sp-decoder.patch).
 
 > Short on time? **5 min** → this page · **20 min** → chapter 1 · **30 min** → the two
-> detective stories (3 & 4) · **the twist** → 5 · **the finale** → 6 · **everything** →
+> detective stories (3 & 4) · **the twist** → 6 · **the finale** → 7 · **everything** →
 > [docs/](docs/) in order, "impossible for thirty years" to "production in a weekend."
 
+## Where it stands now
+
+The work didn't stop at our own servers — it's being handed back to the tools everyone else uses:
+
+- **Into FFmpeg.** FFmpeg is the audio/video engine inside VLC, Chrome, OBS and much of
+  the internet. The Olympus DS2 decoder + demuxer and the DSS-SP paused-recording fix
+  have been **submitted to the `ffmpeg-devel` mailing list and are in review**; the
+  Grundig SP decoder patch is staged behind them. Once merged, *every* program built on
+  FFmpeg reads these files for free, forever — no recipe required.
+- **A public specification.** [The first one ever written](docs/SPEC-grundig-dss-sp.md)
+  for the Grundig DSS-SP codec, bit-exact — so nobody has to reverse-engineer it again.
+- **Digital preservation.** A [PRONOM submission](docs/preservation/PRONOM-submission.md)
+  so archives and forensic tools can even *recognise* these files in the first place.
+
+That's the throughline of the project: not just open the lock for ourselves, but leave
+the door open for everyone.
+
 ## Real-world numbers
 
 The decision to ship rested on **an A/B against the reference Windows implementation
@@ -131,7 +177,7 @@ sample. [Full methodology →](docs/03-validation-campaign.md)
 - 📖 **[docs/](docs/)** — the full didactic trail above, plus [the benchmarks](docs/benchmarks/).
 - 🛠 **[src/](src/)** — the integration code: CLI, cron, HTTP daemon, admin web UI. Sanitized; the patterns are reusable as-is.
 - 🎙 **[grundig/](grundig/)** — the native Grundig DSS-SP decoder (pure Python, bit-exact) + its tables.
-- 🎬 **[ffmpeg-upstream/](ffmpeg-upstream/)** — the FFmpeg patches (DS2 container generalization + the Grundig SP decoder), staged for upstream.
+- 🎬 **[ffmpeg-upstream/](ffmpeg-upstream/)** — the FFmpeg patches (DS2 decoder + demuxer, the DSS-SP paused-recording fix, and the Grundig SP decoder), the ones submitted to `ffmpeg-devel` plus their test samples and cover notes.
 - 📐 **[the formal spec](docs/SPEC-grundig-dss-sp.md)** — the world's first public specification of the Grundig DSS-SP codec (bit-exact), plus a [PRONOM submission](docs/preservation/PRONOM-submission.md) so digital-preservation tools can identify these files at all.
 
 ## Credits — proper order