fix: retention dead when name contains a directory (basename the stem)

rolled files land in log_dir under their basename (the namer/rotate_on_start basename
them), but prune()/retier() globbed the un-basenamed name. a name like 'sub/run' matched
nothing, so old .log/.gz files piled up forever (slow disk leak; the live file was fine).
basename the stem at the top of both prune() and retier(). regression-verified with
name='sub/run' (10 retained vs 12/dead before). bump v0.4.0 -> v0.4.1

Signed-off-by: disqualifier <dev@disqualifier.me>

README.md

@@ -13,12 +13,12 @@ and emit; their records flow into the handlers `log_setup` wired.
 ## Install
 
 ```
-log_setup @ git+ssh://git@git.rethinkstudios.io/rethink-public/log_setup.git@v0.4.0
+log_setup @ git+ssh://git@git.rethinkstudios.io/rethink-public/log_setup.git@v0.4.1
 ```
 
 No dependencies — stdlib only.
 
-Drop the `@v0.4.0` suffix from the line above to install the latest unpinned.
+Drop the `@v0.4.1` suffix from the line above to install the latest unpinned.
 
 ## Quick start
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "log_setup"
-version = "0.4.0"
+version = "0.4.1"
 description = "stdlib app-entry-point logging setup: live run.log, rotation, gzip, retention, consistent format"
 requires-python = ">=3.10"
 dependencies = []

src/log_setup/__init__.py

@@ -19,4 +19,4 @@ from .setup import setup_logging
 
 __all__ = ["setup_logging"]
 
-__version__ = "0.4.0"
+__version__ = "0.4.1"

src/log_setup/rotation.py

@@ -154,7 +154,13 @@ def retier(log_dir: str, stem: str, keep_uncompressed: int, keep_compressed: int
     to <name>.gz and the plain source removed), and everything beyond
     keep_uncompressed+keep_compressed is deleted. the live <stem>.log is never touched.
     fail-soft per file (skip on OSError) so retention never crashes setup.
+
+    `stem` is reduced to its basename: rolled files land in log_dir under the basename
+    (the namer/rotate_on_start basename them), so a `name` containing a directory (e.g.
+    "sub/run") must be matched by "run." here or nothing matches and retention silently
+    never fires (unbounded pileup).
     """
+    stem = os.path.basename(stem)
     try:
         names = [
             name for name in os.listdir(log_dir)
@@ -188,9 +194,14 @@ def prune(log_dir: str, stem: str, backup_count: int) -> None:
 
     matches files beginning with `<stem>.` (e.g. run.*), sorted by mtime, deleting the
     oldest beyond the count. used for on_start, which the handlers don't auto-prune.
+
+    `stem` is reduced to its basename so a `name` containing a directory (e.g. "sub/run")
+    still matches the basenamed rolled files in log_dir (else nothing matches and old
+    files pile up forever).
     """
     if backup_count <= 0:
         return
+    stem = os.path.basename(stem)
     try:
         entries = [
             os.path.join(log_dir, name)