Steps 7 and 8: torrents, OPML, and polish

librqbit replaces the vendored BitTorrent 4.2.1 tree. Torrents download
in place because seeding serves the files it downloaded, so the planned
stage-then-move would have broken it. The stall budget now also covers
magnet metadata resolution, which otherwise never returns against a dead
swarm and wedged the scan.

Adds add/rm/import/export, tracing setup, systemd units and README.

A successful swarm download is unverified: no reachable peers here.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RPyeapneuXrCdojsaiXGbe

src/config.rs

@@ -188,6 +188,33 @@ fn default_socket() -> PathBuf {
     }
 }
 
+/// Feed ids are the TOML table key, so they must be readable and punctuation-free.
+pub fn slug(text: &str) -> String {
+    let mut out = String::new();
+    for c in text.chars() {
+        if c.is_ascii_alphanumeric() {
+            out.push(c.to_ascii_lowercase());
+        } else if c.is_alphanumeric() {
+            out.push(c); // Keep non-ASCII letters; TOML bare keys are stricter, but we quote.
+        } else if !out.ends_with('-') {
+            out.push('-');
+        }
+    }
+    let out = out.trim_matches('-').to_owned();
+    let out: String = out.chars().take(40).collect();
+    let out = out.trim_matches('-').to_owned();
+    if out.is_empty() { "feed".into() } else { out }
+}
+
+/// `slug`, with a numeric suffix if that id is taken.
+pub fn unique_slug(text: &str, taken: &BTreeMap<String, Feed>) -> String {
+    let base = slug(text);
+    if !taken.contains_key(&base) {
+        return base;
+    }
+    (2..).map(|n| format!("{base}-{n}")).find(|s| !taken.contains_key(s)).unwrap()
+}
+
 fn home() -> PathBuf {
     dirs::home_dir().unwrap_or_else(|| PathBuf::from("."))
 }
@@ -241,6 +268,24 @@ mod tests {
         assert_eq!(t.ports(), (6881, 6889), "reversed range is not a range");
     }
 
+    #[test]
+    fn slugs_are_readable_and_unique() {
+        assert_eq!(slug("Accidental Tech Podcast"), "accidental-tech-podcast");
+        assert_eq!(slug("  The Daily!! "), "the-daily");
+        assert_eq!(slug("99% Invisible"), "99-invisible");
+        assert_eq!(slug("///"), "feed");
+        assert_eq!(slug("").len(), 4);
+        assert!(slug(&"x".repeat(100)).len() <= 40);
+
+        let mut taken = BTreeMap::new();
+        taken.insert("the-daily".to_string(), Feed {
+            url: "u".into(), folder: None, keywords: vec![], allow_explicit: false,
+            auto_download: true, max_new_per_check: None, username: None,
+            password: None, password_env: None,
+        });
+        assert_eq!(unique_slug("The Daily", &taken), "the-daily-2");
+    }
+
     #[test]
     fn password_env_wins_over_literal() {
         let mut f = Feed {