Docs: write project README

Add full README covering purpose, the four privacy vulnerabilities
detected (address reuse, dust spend, UTXO consolidation, CIOH),
usage instructions, project structure, and a privacy notice.

README.md

@@ -1 +1,43 @@
-# stealth
+# Stealth
+
+A privacy audit tool for Bitcoin wallets. Stealth analyzes the transaction history of a wallet descriptor and surfaces privacy vulnerabilities at the UTXO level.
+
+## What it does
+
+Paste a Bitcoin wallet descriptor into the input screen and click **Analyze**. Stealth fetches the on-chain history for all addresses derived from that descriptor, then produces a report listing every UTXO in the wallet and the privacy flaws associated with each one.
+
+## Vulnerabilities detected
+
+### Address Reuse
+Detects when the same address has received more than one payment. Address reuse is one of the most damaging privacy practices in Bitcoin: it links multiple transactions to a single entity and permanently exposes the full balance history of that address to anyone inspecting the chain.
+
+### Dust Spend
+Identifies UTXOs that originated from dust attacks — tiny amounts sent by a third party specifically to track a wallet. When the user later spends that dust alongside their own coins, the inputs are merged, linking previously unconnected addresses and revealing ownership clusters.
+
+### UTXO Consolidation
+Flags transactions where multiple UTXOs were combined into a single output. Consolidation is a strong on-chain signal that all the input addresses belong to the same wallet (the Common Input Ownership Heuristic). The resulting UTXO carries the taint of every address that funded it.
+
+### CIOH (Common Input Ownership Heuristic)
+Detects UTXOs that were created by, or whose history involves, transactions where inputs from different addresses were co-signed. This is the foundational clustering heuristic used by chain-analysis firms to link addresses to a single entity.
+
+## How to use
+
+1. Open the application.
+2. On the first screen, paste your wallet descriptor into the input field.
+   - Supported formats: `wpkh(...)`, `pkh(...)`, `sh(wpkh(...))`, `tr(...)`, and multisig variants.
+3. Click **Analyze**.
+4. Review the results:
+   - A list of all UTXOs currently held by the wallet.
+   - For each UTXO, the privacy vulnerabilities detected in its history are highlighted.
+
+## Project structure
+
+```
+stealth/
+├── frontend/   # User interface
+└── backend/    # Descriptor parsing, chain data fetching, and analysis engine
+```
+
+## Privacy notice
+
+Stealth does **not** store, log, or transmit your wallet descriptor or any derived keys. All analysis is read-only and uses publicly available on-chain data. However, querying a third-party node or API for your transaction history may itself reveal your addresses to that service. For maximum privacy, point the backend at your own Bitcoin node.