Pin RSS <title> as the only source of an episode title

Confirmed byte-for-byte against a live feed, and tested against a fixture
whose itunes:title differs: the RSS title wins, and season/episode stay
metadata rather than being folded into the displayed name. An item with a
season but no episode number keeps a null episode instead of inventing one.

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

PROGRESS.md

@@ -56,6 +56,24 @@ and until now nothing set them.
 
 ---
 
+## 2026-09-10 — Titles: RSS `<title>` is the only source
+
+Confirmed against the live feed rather than assumed: 131 feed items, 131 stored, **0 mismatches** —
+entry titles are byte-for-byte what the RSS `<title>` publishes, separators included. `feed.rs` never
+consults `itunes:title`, and season/episode live in their own columns, rendered as chips rather than
+folded into the title.
+
+Pinned with a test: a fixture whose `itunes:title` differs from its `<title>` must still yield the
+RSS title, and an item with `itunes:season` but no `itunes:episode` keeps a null episode instead of
+inventing one.
+
+That null-episode case is real in the wild — this feed's `Music from a Darkened Room | Session Zero`
+carries S8 with no episode number, while Parts 1-5 get E1-E5, and it drops the "Part N" convention
+its siblings use. The arc is 11 items: Session Zero plus five parts, each part being a main episode
+and its shorter `Junk in the Trunk` companion.
+
+---
+
 ## 2026-09-10 — Phase 3: full-featured UI
 
 Rewrite of `web/index.html` (~714 lines) plus the backend it needed.