refactor(subtitles): rename SubtitleCandidate → SubtitleScanResult

The old name conflated 'might become a placed subtitle' with 'what a
scan pass produced'. The class is the output of a scan/identify pass —
language/format may still be None while classification is in progress,
confidence reflects classifier certainty, raw_tokens holds filename
fragments under analysis. SubtitleScanResult says that directly.

Pure rename + refreshed docstring; no behavior change. Touches the
domain entity, the matcher/identifier/utils services, the
manage_subtitles use case, the placer, the metadata store, the
shared-media cross-ref comment, and 7 test modules.

CHANGELOG.md

@@ -68,6 +68,18 @@ callers).
 
 ### Changed
 
+- **`SubtitleCandidate` renamed to `SubtitleScanResult`.** The old name
+  conflated "this might become a placed subtitle" with "this is what a
+  scan pass produced". The class is the output of a scan/identify pass
+  — language/format may still be `None`, confidence reflects how sure
+  the classifier is, and `raw_tokens` holds the filename fragments
+  under analysis. `SubtitleScanResult` says that directly. Pure rename
+  with a refreshed docstring in `alfred/domain/subtitles/entities.py`;
+  no behavior change. Touches the domain entity + `__init__` export,
+  the matcher / identifier / utils services, the manage_subtitles use
+  case, the placer, the metadata store, the shared-media cross-ref
+  comment, and the seven test modules that imported the type.
+
 - **`ParsedRelease` is now frozen; enrichment passes return new
   instances.** The VO was mutable so `detect_media_type` and
   `enrich_from_probe` could patch fields in place — a code smell in a