Cargo workspace: crates/ipx and a shared crates/feed (#202)

The first step of the split (#207). The daemon moves to crates/ipx unchanged;
feed.rs becomes crates/feed (ipx-feed), which the directory service (#204)
will share for its metadata refresher and its privacy check.

To stand alone, fetch takes the feed's address and its credentials instead
of ipx's config::Feed (config::Feed::auth gives them), collect_outlines
moves in with the OPML parsing, and the address half of looks_private is
feed::url_looks_private. ipx imports the crate as `feed` at its root, so
every crate::feed path is unchanged. The version is the workspace's, in the
root Cargo.toml.

Checked: cargo test on Postgres (118 + 29), tsc, page smoke, native bridge,
contrast and Playwright (72) pass; the image built from the new Dockerfile
is deployed and healthy.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -1830,6 +1830,7 @@ dependencies = [
  "chrono",
  "clap",
  "futures-util",
+ "ipx-feed",
  "jsonwebtoken",
  "librqbit",
  "opentelemetry",
@@ -1854,6 +1855,23 @@ dependencies = [
  "url",
 ]
 
+[[package]]
+name = "ipx-feed"
+version = "0.12.1-dev"
+dependencies = [
+ "anyhow",
+ "atom_syndication",
+ "chrono",
+ "opml",
+ "quick-xml 0.42.0",
+ "reqwest",
+ "rss",
+ "serde_json",
+ "tokio",
+ "tracing",
+ "url",
+]
+
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.2"