Merge agent-trust-wip (DHT Phases 0–4) into main

Integrates the DHT/peer-distribution line with the v1.7.98-alpha release
fixes:
- Phase 0 signed-catalog trust + release-root key (KAT-pinned)
- Phase 1 BLAKE3 content addressing alongside SHA-256
- Phase 2 swarm-assist fetch seam (origin always wins) + iroh-blobs
  provider — heavy iroh deps stay behind the off-by-default `iroh-swarm`
  feature, so the default build/deploy is unaffected
- Phase 3 signed Nostr seed-advertisement + discovery glue + paid swarm
  serving + "Networking Profits" Settings page
- Phase 4 paid swarm streaming (cross-mint ecash, Shape-A paid ALPN,
  streaming.prepare-payment), also iroh-swarm-gated

Conflicts resolved: seed.rs (kept release-root KAT tests), update.rs
(comment-only, OTA logic identical), Cargo.lock (regenerated against the
merged Cargo.toml). Default-feature build is clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

core/archipelago/src/update.rs

@@ -263,6 +263,11 @@ pub struct ComponentUpdate {
     pub download_url: String,
     pub sha256: String,
     pub size_bytes: u64,
+    /// DHT Phase 1: BLAKE3 content address (bare hex or `"blake3:<hex>"`), the
+    /// iroh-native, range-verifiable hash. Optional during the migration
+    /// window — when present it is verified ALONGSIDE the mandatory SHA-256.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub blake3: Option<String>,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
@@ -798,7 +803,53 @@ pub async fn download_update(data_dir: &Path) -> Result<DownloadProgress> {
         }
         info!(name = %component.name, url = %component.download_url, "Downloading component");
         let dest = staging_dir.join(&component.name);
-        download_component_resumable(&client, component, &dest, downloaded).await?;
+
+        // DHT Phase 2: when the manifest pins a BLAKE3 digest, route the fetch
+        // through the swarm seam (swarm-assist, origin always wins). With no
+        // providers registered (iroh-swarm feature off) this is identical to
+        // calling the resumable HTTP origin directly — same bytes, now
+        // content-addressed. A swarm hit is BLAKE3-verified inside the seam;
+        // we still enforce the mandatory SHA-256 gate on peer bytes here and
+        // re-fetch from origin if a (consistency-broken) peer slips through.
+        let digest = component.blake3.as_deref().and_then(|b| {
+            let s = b.trim();
+            let normalized = if s.contains(':') {
+                s.to_string()
+            } else {
+                format!("blake3:{s}")
+            };
+            crate::content_hash::ContentDigest::parse(&normalized).ok()
+        });
+        if let Some(digest) = digest {
+            let client_ref = &client;
+            let dest_ref = &dest;
+            let source = crate::swarm::fetch_content_addressed(
+                &digest,
+                &crate::swarm::providers(),
+                &dest,
+                move || async move {
+                    download_component_resumable(client_ref, component, dest_ref, downloaded).await
+                },
+            )
+            .await?;
+            if source == crate::swarm::FetchSource::Swarm {
+                let bytes = tokio::fs::read(&dest).await?;
+                if crate::content_hash::sha256_hex(&bytes) != component.sha256 {
+                    warn!(
+                        name = %component.name,
+                        "swarm bytes passed BLAKE3 but failed the SHA-256 manifest gate — re-fetching from origin"
+                    );
+                    let _ = tokio::fs::remove_file(&dest).await;
+                    download_component_resumable(&client, component, &dest, downloaded).await?;
+                }
+            }
+            // This is a PUBLIC release blob and it just passed both the BLAKE3 and
+            // SHA-256 gates — announce that we can now seed it to peers. Best-effort
+            // and inert unless the iroh swarm is active; never blocks the install.
+            crate::swarm::announce_held_blob(&digest.hex, &dest).await;
+        } else {
+            download_component_resumable(&client, component, &dest, downloaded).await?;
+        }
         downloaded += component.size_bytes;
         DOWNLOAD_BYTES.store(downloaded, Ordering::Relaxed);
         info!(
@@ -993,6 +1044,25 @@ async fn download_component_resumable(
             .context("read staging file for hash check")?;
         let hash = hex::encode(Sha256::digest(&bytes));
         if hash == component.sha256 {
+            // DHT Phase 1: if the manifest also pins a BLAKE3 digest, it must
+            // match too. SHA-256 stays the mandatory gate during migration;
+            // BLAKE3 is the hash the iroh swarm will fetch/verify by, so a
+            // present-but-wrong BLAKE3 means the bytes aren't swarm-consistent
+            // — treat it like a SHA mismatch and re-download.
+            if let Some(b3) = component.blake3.as_deref() {
+                let expected = b3.trim().strip_prefix("blake3:").unwrap_or(b3.trim());
+                let actual = crate::content_hash::blake3_hex(&bytes);
+                if !actual.eq_ignore_ascii_case(expected) {
+                    let _ = tokio::fs::remove_file(dest).await;
+                    last_err = Some(anyhow::anyhow!(
+                        "BLAKE3 mismatch for {}: expected {}, got {}",
+                        component.name,
+                        expected,
+                        actual
+                    ));
+                    continue;
+                }
+            }
             return Ok(());
         }
         // SHA mismatch — the file on disk is garbage. Nuke it and
@@ -1675,6 +1745,7 @@ mod tests {
                     download_url: "https://git.tx1138.com/lfg2025/archy/raw/branch/main/releases/v1.7.26-alpha/archipelago".into(),
                     sha256: "x".into(),
                     size_bytes: 1,
+                    blake3: None,
                 },
                 ComponentUpdate {
                     name: "frontend".into(),
@@ -1683,6 +1754,7 @@ mod tests {
                     download_url: "https://git.tx1138.com/lfg2025/archy/raw/branch/main/releases/v1.7.26-alpha/frontend.tar.gz".into(),
                     sha256: "y".into(),
                     size_bytes: 2,
+                    blake3: None,
                 },
             ],
         };
@@ -1882,9 +1954,10 @@ mod tests {
         tokio::fs::write(staging.join("archipelago"), b"staged")
             .await
             .unwrap();
-        // A *complete* staged update carries the marker; without it the state
-        // self-heal correctly treats this as a partial download and clears
-        // update_in_progress (see has_staged_update / #26).
+        // A *complete* staged update carries the .download-complete marker;
+        // without it has_staged_update() reads the staging as partial and the
+        // load_state self-heal clears update_in_progress (see #26). This test
+        // simulates a complete staging, so write the marker.
         tokio::fs::write(staging.join(STAGED_COMPLETE_MARKER), b"1")
             .await
             .unwrap();
@@ -1902,6 +1975,7 @@ mod tests {
                     download_url: "https://example.com/binary".to_string(),
                     sha256: "abc123".to_string(),
                     size_bytes: 5000,
+                    blake3: None,
                 }],
             }),
             update_in_progress: true,