chore: prepare the 3.8.1 release

Bumps src.__version__ to 3.8.1 and moves the Unreleased CHANGELOG entries
under a 3.8.1 heading, with an empty Unreleased above it.

The reason for the release is smooth scrolling at held-frame speeds. On
3.8.0 the default 50 px/s snapped to a stepped 48 px/s on a 120 Hz panel,
and any scroll slower than one pixel per refresh showed a half-pixel step
across the middle of the panel. Both are fixed on main (#710, #711) but
were in no release, so every stable-channel device still had them.

- #710's CHANGELOG entry had been filed under 3.8.0 although it merged
  after the v3.8.0 tag; it moves to 3.8.1.
- #711 had no CHANGELOG entry; it gets one.

scripts/check_release_version.py v3.8.1 passes.

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

CHANGELOG.md

@@ -19,6 +19,40 @@ accepts both, but the store flags the old spelling as deprecated
 
 ## Unreleased
 
+## 3.8.1
+
+Smooth scrolling at the slower speeds, and the fixes and performance work
+since 3.8.0. Highlights: the default 50 px/s and every other held-frame speed
+now scroll cleanly (below), Raspberry Pi OS Bookworm is supported alongside
+Trixie, updates refresh the systemd units, the display control socket gains
+stages 2 and 3, the shared fetch service lands (stages 1 and 2), and a run of
+web UI and Plugin Manager fixes. The new modules are core-internal and set no
+`ledmatrix_min_version` floor.
+
+### Scroll speed
+
+These two entries were the reason for this release: on 3.8.0 a slow scroll
+either stepped or showed a half-pixel tear across the middle of the panel,
+so only speeds of one pixel per refresh looked right.
+
+- The Vegas Scroll Speed slider now says what the panel will do with the speed
+  it is on, and offers the nearest smooth ones to click. Only speeds that advance
+  a whole number of pixels per refresh look smooth, and which those are depends
+  on the panel (`GET /api/v3/config/scroll-speed-advice`, built on
+  `scroll_config.speed_advice()`; it uses the refresh the display measured, not
+  the `limit_refresh_rate_hz` cap). The slider steps by 1 px/s instead of 5.
+- The default 50 px/s no longer snaps to a stepped 48 px/s (2 px every 5
+  refreshes, 24 fps) on a 120 Hz panel: `solve_crisp()` now prefers 60 or 40 px/s,
+  which move one pixel at a time. 100 Hz panels are unaffected. (#710)
+- A held-frame scroll (one pixel every two or more refreshes, such as 50 or
+  60 px/s on a 100-120 Hz panel) no longer shows a half-pixel step across the
+  middle of the panel. Scan-order compensation ran only at one frame per
+  refresh; a held frame is now presented as a sequence of swaps
+  (`scan_order.refresh_plan()`), so the half of the panel that scans later
+  steps one refresh after the rest. It is skipped when a blit takes more than
+  half a refresh, since the second blit has to land before the next vsync.
+  (#711)
+
 ### Fixed
 
 - The web preview and `/api/v3/display/current` no longer stay black for a
@@ -57,18 +91,6 @@ soccer-scoreboard 2.39.2, alternating runs: **~450 requests per start, peak
   spends one doomed 400 per window at every start (eleven at once from a
   soccer board); the range is still retried `RANGE_RETRY_SECONDS` in.
 
-### Fetch stats: bytes on the wire, not just decoded
-
-`GET /api/v3/plugins/fetch-stats` reported only `bytes`, the decoded body
-size, and that read as the download volume. ESPN gzips every scoreboard, so
-it overstated what crossed the network about 14x: a college football
-Saturday's scoreboard is 865 KB decoded and 63 KB on the wire, and ledpi's
-"643 MB in 6 hours" of football was ~47 MB of actual traffic. Every counter
-set (totals, per plugin, per host) now has `wire_bytes` too, read from
-urllib3's count of the raw bytes it took off the socket. A response with no
-urllib3 response behind it is counted at its decoded size. `bytes` keeps its
-meaning.
-
 ### Cheap per-frame and per-fetch savings
 
 - `BaseOddsManager.get_odds()` no longer pretty-prints every odds response
@@ -1160,18 +1182,6 @@ guard the import, since the loader's version check is advisory).
   processes, or turns the socket off with `off`. A non-root dev run uses a
   private per-user path under the temp directory.
 
-### Scroll speed
-
-- The Vegas Scroll Speed slider now says what the panel will do with the speed
-  it is on, and offers the nearest smooth ones to click. Only speeds that advance
-  a whole number of pixels per refresh look smooth, and which those are depends
-  on the panel (`GET /api/v3/config/scroll-speed-advice`, built on
-  `scroll_config.speed_advice()`; it uses the refresh the display measured, not
-  the `limit_refresh_rate_hz` cap). The slider steps by 1 px/s instead of 5.
-- The default 50 px/s no longer snaps to a stepped 48 px/s (2 px every 5
-  refreshes, 24 fps) on a 120 Hz panel: `solve_crisp()` now prefers 60 or 40 px/s,
-  which move one pixel at a time. 100 Hz panels are unaffected.
-
 ### Update channels
 
 - Devices no longer pick up every merge to `main`. A new setting,

src/__init__.py

@@ -4,5 +4,5 @@ LEDMatrix Display System
 Core source package for the LED Matrix Display project.
 """
 
-__version__ = "3.8.0"
+__version__ = "3.8.1"
 

src/common/fetch_service.py

@@ -59,10 +59,7 @@ says how old with ``cache_max_age`` (``fetch_get(..., cache_max_age=ttl)``;
 Identical means what the validator store keys on: URL, query, effective
 headers and, for a session with cookies or auth, the session.
 
-**Counters.** Requests, merged requests, bytes (``bytes`` decoded, as the
-caller reads them; ``wire_bytes`` as they crossed the network, which is
-what a metered connection pays for -- ESPN gzips, so the two differ ~14x),
-304s, errors, HTTP errors,
+**Counters.** Requests, merged requests, bytes, 304s, errors, HTTP errors,
 adapter retries, throttled requests and seconds waited, plus requests
 answered without the network: ``memo_hits`` (the response cache) and
 ``cache_hits`` / ``legacy_cache_hits`` (a shared ESPN scoreboard cache entry,
@@ -204,7 +201,6 @@ _COUNTER_FIELDS = (
     "throttled",     # requests that waited for a host budget
     "overruns",      # requests that went after max_wait_seconds anyway
     "bytes",         # decoded response body bytes received
-    "wire_bytes",    # body bytes as they came off the socket (still compressed)
     "wait_seconds",  # time spent waiting for host budgets
     "memo_hits",     # answered from the response cache (max-age); nothing sent
     "cache_hits",    # scoreboard fetches answered from a shared ESPN cache entry
@@ -620,30 +616,6 @@ def _body_of(response: Any) -> Optional[bytes]:
     return content if isinstance(content, bytes) else None
 
 
-def _wire_bytes_of(response: Any, body: Optional[bytes]) -> int:
-    """How many body bytes came off the socket for ``response``: the
-    compressed size when the server sent gzip, which ESPN does for every
-    scoreboard (63 KB on the wire for an 865 KB college football Saturday).
-
-    urllib3's ``HTTPResponse.tell()`` counts the raw bytes read before
-    decoding. A response without one (a test double, an adapter that is not
-    urllib3) or one whose body was not read is counted at its decoded size,
-    or as 0, so the counter never claims less than it can prove.
-    """
-    if body is None:
-        return 0
-    raw = getattr(response, "raw", None)
-    tell = getattr(raw, "tell", None)
-    if callable(tell):
-        try:
-            read = tell()
-        except Exception:
-            read = None
-        if isinstance(read, int) and not isinstance(read, bool) and read > 0:
-            return read
-    return len(body)
-
-
 def _retries_of(response: Any) -> int:
     raw = getattr(response, "raw", None)
     retries = getattr(raw, "retries", None)
@@ -1145,7 +1117,6 @@ class FetchService:
                         http_errors=int(status is not None and status >= 400),
                         retries=_retries_of(response),
                         bytes=len(body) if body is not None else 0,
-                        wire_bytes=_wire_bytes_of(response, body),
                         throttled=int(waited > 0), overruns=int(overrun),
                         wait_seconds=waited)
         except Exception:

test/test_fetch_service.py

@@ -576,42 +576,6 @@ class TestCounters:
         assert snap["hosts"]["site.api.espn.com"]["requests"] == 1
         assert snap["totals"]["bytes"] == 3 * len(b'{"ok": 1}')
 
-    def test_wire_bytes_are_the_compressed_size(self, service):
-        # Built the way requests builds a real response: a urllib3
-        # HTTPResponse carrying a gzip body, decoded when .content is read.
-        import gzip
-        import io
-
-        from requests.adapters import HTTPAdapter
-        from urllib3.response import HTTPResponse
-
-        decoded = json.dumps({"events": [{"id": str(i), "name": "x" * 200}
-                                         for i in range(50)]}).encode()
-        wire = gzip.compress(decoded)
-
-        def handler(url, kwargs):
-            raw = HTTPResponse(body=io.BytesIO(wire), status=200,
-                               headers={"Content-Encoding": "gzip",
-                                        "Content-Type": "application/json"},
-                               preload_content=False, decode_content=True)
-            request = requests.Request("GET", url).prepare()
-            response = HTTPAdapter().build_response(request, raw)
-            response.content  # what Session.get does for a non-streamed call
-            return response
-
-        response = service.get(FakeSession(handler), "https://site.api.espn.com/x")
-        assert response.content == decoded
-        totals = _counters(service)
-        assert totals["bytes"] == len(decoded)
-        assert totals["wire_bytes"] == len(wire) < len(decoded)
-
-    def test_wire_bytes_fall_back_to_the_decoded_size(self, service):
-        # No urllib3 response behind it (a test double, another adapter):
-        # count what is known rather than nothing.
-        service.get(FakeSession(), "https://api.test/x")
-        totals = _counters(service)
-        assert totals["wire_bytes"] == totals["bytes"] == len(b'{"ok": 1}')
-
     def test_errors_and_http_errors(self, service):
         def handler(url, kwargs):
             if url.endswith("/down"):