Keep the feed catalogue and server settings in the database

Phase 3 of #18. Two tables: catalogue (each feed's config::Feed as JSON, so a
new feed setting needs no column) and settings (general: the five server
settings the admin page edits). config.toml keeps what is needed before the
database is reached, or decides who gets in: paths, [torrent], [web].

ipx still runs from one in-memory Config, assembled at start from both
(assemble_config). The eight places that saved config.toml and re-read it now
call Ctx::store_cfg, which writes the database and swaps the copy in memory; the
first-run web token, which is config.toml's, is written there.

The first start on a database with no catalogue imports config.toml's feeds and
settings in one transaction whose first insert is the settings row, so two ipx
starting at once cannot both import; it then trims config.toml, keeping the
original as config.toml.pre-database. After that, feeds written into the file are
ignored with a warning. copy-db skips it, and copies both tables.

Rehearsed on a clone of production's database with production's config: all 130
feeds imported, the file trimmed, and the feed list, settings and directory
identical to the live server's.

Postgres connections now ask for no notices. Every CREATE ... IF NOT EXISTS on an
existing table sends one, eleven per open; sqlx logs them, and
tracing-subscriber 0.3.23's per-layer filters then dropped the next line ipx
logged -- the import's own message went missing that way. Proved by toggling it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/config.rs

@@ -261,21 +261,86 @@ impl Config {
         Ok(cfg)
     }
 
-    pub fn save(&self, path: &Path) -> Result<()> {
-        if let Some(dir) = path.parent() {
-            std::fs::create_dir_all(dir)
-                .with_context(|| format!("creating {}", dir.display()))?;
+}
+
+/// What the database keeps of the configuration (issue #18): the server settings the admin page
+/// edits, and, beside them in `Db::stored_config`, the catalogue of feeds. The rest -- where
+/// things are, who may sign in, the torrent session -- is needed before the database is reached,
+/// or decides who gets in, and stays in config.toml.
+#[derive(Debug, Clone, PartialEq, Deserialize, Serialize)]
+pub struct Stored {
+    pub schedule: String,
+    pub max_total_gb: f64,
+    pub max_age_days: u64,
+    pub max_new_per_check: usize,
+    pub media_types: Vec<String>,
+}
+
+/// `[general]` keys that live in the database once it holds the configuration.
+const STORED_KEYS: [&str; 5] = ["schedule", "max_total_gb", "max_age_days", "max_new_per_check", "media_types"];
+
+impl Stored {
+    pub fn of(cfg: &Config) -> Self {
+        let g = &cfg.general;
+        Self {
+            schedule: g.schedule.clone(),
+            max_total_gb: g.max_total_gb,
+            max_age_days: g.max_age_days,
+            max_new_per_check: g.max_new_per_check,
+            media_types: g.media_types.clone(),
         }
-        let text = toml::to_string_pretty(self)?;
-        std::fs::write(path, text).with_context(|| format!("writing {}", path.display()))?;
-        // Passwords may live in here.
-        #[cfg(unix)]
-        {
-            use std::os::unix::fs::PermissionsExt;
-            std::fs::set_permissions(path, std::fs::Permissions::from_mode(0o600))?;
-        }
-        Ok(())
     }
+
+    pub fn apply(self, cfg: &mut Config) {
+        let g = &mut cfg.general;
+        g.schedule = self.schedule;
+        g.max_total_gb = self.max_total_gb;
+        g.max_age_days = self.max_age_days;
+        g.max_new_per_check = self.max_new_per_check;
+        g.media_types = self.media_types;
+    }
+}
+
+impl Config {
+    /// config.toml as it is kept once the database holds the feeds and server settings: the same
+    /// file without `[feeds]` or the `[general]` keys in `Stored`.
+    pub fn save_bootstrap(&self, path: &Path) -> Result<()> {
+        let mut v = toml::Value::try_from(self)?;
+        if let Some(t) = v.as_table_mut() {
+            t.remove("feeds");
+            if let Some(g) = t.get_mut("general").and_then(|g| g.as_table_mut()) {
+                for k in STORED_KEYS {
+                    g.remove(k);
+                }
+            }
+        }
+        write_private(path, &toml::to_string_pretty(&v)?)
+    }
+
+    /// Whether config.toml still lists feeds or server settings, which the database now holds:
+    /// an edit there would otherwise go unnoticed.
+    pub fn file_holds_stored(path: &Path) -> bool {
+        let Ok(text) = std::fs::read_to_string(path) else { return false };
+        let Ok(v) = text.parse::<toml::Table>() else { return false };
+        v.get("feeds").and_then(|f| f.as_table()).is_some_and(|f| !f.is_empty())
+            || v.get("general")
+                .and_then(|g| g.as_table())
+                .is_some_and(|g| STORED_KEYS.iter().any(|k| g.contains_key(*k)))
+    }
+}
+
+/// Writes a config file readable by its owner alone: feed passwords have lived in it.
+fn write_private(path: &Path, text: &str) -> Result<()> {
+    if let Some(dir) = path.parent() {
+        std::fs::create_dir_all(dir).with_context(|| format!("creating {}", dir.display()))?;
+    }
+    std::fs::write(path, text).with_context(|| format!("writing {}", path.display()))?;
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        std::fs::set_permissions(path, std::fs::Permissions::from_mode(0o600))?;
+    }
+    Ok(())
 }
 
 /// `$IPX_CONFIG`, else `$XDG_CONFIG_HOME/ipx/config.toml`.
@@ -370,6 +435,36 @@ fn expand_tilde(p: &Path) -> PathBuf {
 mod tests {
     use super::*;
 
+    #[test]
+    fn the_file_kept_beside_the_database_has_no_feeds_or_server_settings() {
+        let cfg: Config = toml::from_str(
+            r#"
+            [general]
+            download_dir = "/downloads"
+            schedule = "every 2h"
+            max_new_per_check = 7
+            media_types = ["audio"]
+            [web]
+            bind = "0.0.0.0:8099"
+            token = "t"
+            [feeds.show]
+            url = "http://x/show.xml"
+            "#,
+        )
+        .unwrap();
+        let path = std::env::temp_dir().join(format!("ipx-bootstrap-{}.toml", std::process::id()));
+        std::fs::write(&path, toml::to_string(&cfg).unwrap()).unwrap();
+        assert!(Config::file_holds_stored(&path), "a whole config.toml holds them");
+        cfg.save_bootstrap(&path).unwrap();
+        let text = std::fs::read_to_string(&path).unwrap();
+        assert!(!Config::file_holds_stored(&path), "{text}");
+        let back: Config = toml::from_str(&text).unwrap();
+        assert!(back.feeds.is_empty());
+        assert_eq!(back.web.token, "t", "who may sign in stays in the file");
+        assert_eq!(back.general.download_dir, PathBuf::from("/downloads"), "where things are, too");
+        std::fs::remove_file(&path).unwrap();
+    }
+
     #[test]
     fn parses_a_config_and_applies_defaults() {
         let cfg: Config = toml::from_str(