test: add real-world release fixtures (EASY bucket)

Captures 5 canonical releases from /mnt/testipool/downloads as parametrized
fixtures under tests/fixtures/releases/easy/. Each fixture declares the
release name, expected ParsedRelease fields, original tree, and the future
routing (library / torrents / seed_hardlinks) for the upcoming organize_media
refactor.

Today only the 'parsed' section is asserted; tree is materialized into a
tmp_path to catch typos. Routing is captured ahead of the planner work — it
becomes verifiable once organize_media lands.

Cases: back_in_action (movie), slow_horses_single_ep (TV single),
foundation_season_pack (S02 + .nfo noise), long_walk_with_noise (movie +
KONTRAST.TOP.txt), sinners_yts (YTS bracket-heavy + Subs/ dir).

Also tracks CHANGELOG.md under [Unreleased] / Added.

tests/fixtures/releases/easy/back_in_action/expected.yaml

@@ -0,0 +1,30 @@
+release_name: "Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST"
+
+parsed:
+  title: "Back.in.Action"
+  year: 2025
+  season: null
+  episode: null
+  episode_end: null
+  quality: "1080p"
+  source: "WEBRip"
+  codec: "x265"
+  group: "KONTRAST"
+  tech_string: "1080p.WEBRip.x265"
+  media_type: "movie"
+  site_tag: null
+  parse_path: "direct"
+  is_season_pack: false
+
+tree:
+  - "Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST/"
+  - "Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST/Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST.mkv"
+
+routing:
+  library:
+    - "Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST/Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST.mkv"
+  torrents:
+    - "Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST/"
+  seed_hardlinks:
+    - source: "library/Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST/Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST.mkv"
+      target: "torrents/Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST/Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST.mkv"