fix(pixlet): resolve the release tag correctly when downloading

Starlark apps render through the pixlet binary, and the installer that
fetches it silently produced nothing, so every app failed with "Pixlet
not available - Starlark apps will not work".

Two compounding defects:

The version lookup parsed the wrong token. GitHub returns the release
JSON on a single line, so `grep '"tag_name"'` matches the whole document
and the greedy `sed 's/.*"([^"]+)".*/\1/'` captures the LAST quoted
string in it. That resolved to "mentions_count", giving a download URL
for a release that does not exist. The `[ -z "$PIXLET_VERSION" ]`
fallback never fired, because the value was not empty -- just wrong.

And `curl -L -o` without `-f` writes a 404 body to the file and exits 0,
so the download was reported as successful and the first sign of trouble
was tar complaining "not in gzip format" about a page of HTML:

    → Downloading linux-arm64...
      Extracting...
    gzip: stdin: not in gzip format
    ✗ Failed to extract archive: .../pixlet_mentions_count_linux-arm64.tar.gz
    Download complete: 0/1 succeeded

Now the tag field is matched directly and the value taken from it, and
the result is checked for a version shape rather than merely being
non-empty -- a wrong-but-non-empty value is exactly what made this
silent. curl gets -f so an HTTP error is a failure, and the archive is
gzip-tested before extraction, since a proxy can return 200 with an
error page.

Verified on an arm64 rig: v0.53.1 resolved, 1/1 downloaded, the binary
runs, and the plugin's own detection finds it at
bin/pixlet/pixlet-linux-arm64.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Udr6MfaFLUPhX5Fgo67Jf5

.github/workflows/test.yml

@@ -79,4 +79,5 @@ jobs:
             test/test_sports_scroll.py \
             test/test_version_consistency.py \
             test/test_plugin_compatibility_gate.py \
-            test/test_install_preserves_existing.py
+            test/test_install_preserves_existing.py \
+            test/test_core_owned_config_keys.py

scripts/download_pixlet.sh

@@ -24,9 +24,20 @@ echo "========================================"
 # Auto-detect latest version if needed
 if [ "$PIXLET_VERSION" = "latest" ]; then
     echo "Detecting latest version..."
-    PIXLET_VERSION=$(curl -s "https://api.github.com/repos/${REPO}/releases/latest" | grep '"tag_name"' | sed -E 's/.*"([^"]+)".*/\1/')
-    if [ -z "$PIXLET_VERSION" ]; then
-        echo "Failed to detect latest version, using fallback"
+    # GitHub returns this JSON on a single line, so `grep '"tag_name"'`
+    # matches the whole document and a greedy `sed 's/.*"([^"]+)".*/\1/'`
+    # captures the LAST quoted token in it rather than the tag. That resolved
+    # to "mentions_count", which built a download URL for a release that does
+    # not exist. Match the field itself and take the value after it.
+    PIXLET_VERSION=$(curl -fsSL "https://api.github.com/repos/${REPO}/releases/latest" \
+        | grep -o '"tag_name"[[:space:]]*:[[:space:]]*"[^"]*"' \
+        | head -n1 \
+        | sed -E 's/.*:[[:space:]]*"([^"]*)".*/\1/')
+
+    # A wrong-but-non-empty value is what made the old bug silent, so check
+    # the shape rather than just that something came back.
+    if ! printf '%s' "$PIXLET_VERSION" | grep -qE '^v?[0-9]+\.[0-9]+'; then
+        echo "Could not detect the latest version (got: '${PIXLET_VERSION:-<empty>}'), using fallback"
         PIXLET_VERSION="v0.50.2"
     fi
 fi
@@ -67,8 +78,19 @@ download_binary() {
     temp_dir=$(mktemp -d -p "$PROJECT_ROOT" -t pixlet_download.XXXXXXXXXX)
     local temp_file="$temp_dir/$archive_name"
 
-    if ! curl -L -o "$temp_file" "$url" 2>/dev/null; then
-        echo "✗ Failed to download $arch"
+    # -f so an HTTP error is a failure. Without it curl writes the 404 body
+    # to the file and exits 0, and the first sign of trouble is tar saying
+    # "not in gzip format" about what is actually a page of HTML.
+    if ! curl -fL -o "$temp_file" "$url" 2>/dev/null; then
+        echo "✗ Failed to download $arch from $url"
+        rm -rf "$temp_dir"
+        return 1
+    fi
+
+    # Belt and braces: a mirror or proxy can return 200 with an error page.
+    if ! gzip -t "$temp_file" 2>/dev/null; then
+        echo "✗ Downloaded file is not a gzip archive: $url"
+        echo "  (first bytes: $(head -c 60 "$temp_file" | tr -d '\0' | tr '\n' ' '))"
         rm -rf "$temp_dir"
         return 1
     fi

src/plugin_system/plugin_manager.py

@@ -395,6 +395,37 @@ class PluginManager:
             self.state_manager.set_state(plugin_id, PluginState.ERROR, error=e)
             return False
     
+    #: Config keys the **core** reads out of a plugin's own config block. The
+    #: plugin never declares them, so a schema with
+    #: ``"additionalProperties": false`` — 37 of the 42 published ones — reports
+    #: them as violations and the plugin gets flagged degraded in the web UI for
+    #: using a documented core feature.
+    #:
+    #: Listed explicitly rather than matched on a ``vegas_`` prefix, because
+    #: ``vegas_mode`` is the opposite case: plugins *do* declare that one, and a
+    #: prefix rule would silently stop validating it.
+    #:
+    #: Read by: ``vegas_mode/plugin_adapter.py`` (``vegas_width_pct``,
+    #: ``vegas_overflow``) and ``base_plugin.py`` (``vegas_max_width_screens``).
+    CORE_OWNED_CONFIG_KEYS = frozenset({
+        'vegas_width_pct',
+        'vegas_overflow',
+        'vegas_max_width_screens',
+    })
+
+    def _strip_core_owned_keys(self, config: Dict[str, Any]) -> Dict[str, Any]:
+        """A shallow copy of ``config`` without the core's own tuning keys.
+
+        Only the top level is touched, and only when such a key is present, so
+        the common case allocates nothing extra.
+        """
+        if not isinstance(config, dict):
+            return config
+        if not self.CORE_OWNED_CONFIG_KEYS.intersection(config):
+            return config
+        return {k: v for k, v in config.items()
+                if k not in self.CORE_OWNED_CONFIG_KEYS}
+
     def _validate_config_schema_soft(self, plugin_id: str, config: Dict[str, Any]) -> None:
         """Validate a plugin's config against its JSON schema — warn/degrade only.
 
@@ -419,7 +450,7 @@ class PluginManager:
 
         try:
             is_valid, errors = self.schema_manager.validate_config_against_schema(
-                config, schema, plugin_id
+                self._strip_core_owned_keys(config), schema, plugin_id
             )
         except Exception as e:  # pragma: no cover - defensive
             # Validation machinery itself failed — do not penalise the plugin.

test/test_core_owned_config_keys.py

@@ -0,0 +1,98 @@
+"""The core's own tuning keys must not make a plugin look broken.
+
+`vegas_width_pct`, `vegas_overflow` and `vegas_max_width_screens` are read by
+the *core* out of each plugin's config block — `vegas_mode/plugin_adapter.py`
+and `base_plugin.py`. No plugin declares them, and 37 of the 42 published
+config schemas set `"additionalProperties": false`, so schema validation
+reported them as violations.
+
+That is not just log noise: `_validate_config_schema_soft` sets `degraded` in
+the health tracker, which the web UI surfaces. Measured on a real device, **9
+of 27 installed plugins** were flagged degraded purely for using a documented
+core feature — including `baseball-scoreboard` and `f1-scoreboard`.
+
+The fix strips those keys before validating. It deliberately does *not* match
+on a `vegas_` prefix: `vegas_mode` is plugin-owned and declared in schemas, and
+a prefix rule would silently stop validating it.
+"""
+
+from unittest.mock import MagicMock
+
+import pytest
+
+from src.plugin_system.plugin_manager import PluginManager
+
+
+STRICT_SCHEMA = {
+    "type": "object",
+    "additionalProperties": False,
+    "properties": {
+        "enabled": {"type": "boolean"},
+        "vegas_mode": {"type": "string"},  # plugin-owned, must stay validated
+    },
+}
+
+
+@pytest.fixture
+def manager():
+    mgr = PluginManager.__new__(PluginManager)  # skip the heavy constructor
+    mgr.logger = MagicMock()
+    mgr.schema_manager = MagicMock()
+    mgr._set_degraded_safe = MagicMock()
+    return mgr
+
+
+class TestStripCoreOwnedKeys:
+    def test_removes_every_core_owned_key(self, manager):
+        cfg = {"enabled": True, "vegas_width_pct": 50,
+               "vegas_overflow": "wrap", "vegas_max_width_screens": 2}
+        assert manager._strip_core_owned_keys(cfg) == {"enabled": True}
+
+    def test_leaves_plugin_owned_vegas_mode_alone(self, manager):
+        """A prefix rule would have eaten this one."""
+        cfg = {"enabled": True, "vegas_mode": "scroll"}
+        assert manager._strip_core_owned_keys(cfg) == cfg
+
+    def test_returns_the_same_object_when_nothing_to_strip(self, manager):
+        cfg = {"enabled": True}
+        assert manager._strip_core_owned_keys(cfg) is cfg
+
+    def test_does_not_mutate_the_caller_config(self, manager):
+        cfg = {"enabled": True, "vegas_width_pct": 50}
+        manager._strip_core_owned_keys(cfg)
+        assert "vegas_width_pct" in cfg, "the live plugin config was mutated"
+
+    def test_tolerates_a_non_dict(self, manager):
+        assert manager._strip_core_owned_keys(None) is None
+
+
+class TestSoftValidation:
+    def _validate_with(self, manager, config, valid=True, errors=()):
+        manager.schema_manager.load_schema.return_value = STRICT_SCHEMA
+        manager.schema_manager.validate_config_against_schema.return_value = (
+            valid, list(errors))
+        manager._validate_config_schema_soft("baseball-scoreboard", config)
+        return manager.schema_manager.validate_config_against_schema.call_args
+
+    def test_core_keys_never_reach_the_validator(self, manager):
+        """The regression: these keys reaching a strict schema is what flagged
+        9 of 27 plugins degraded."""
+        args = self._validate_with(
+            manager, {"enabled": True, "vegas_width_pct": 50})
+        validated = args[0][0]
+        assert "vegas_width_pct" not in validated
+        assert validated == {"enabled": True}
+
+    def test_plugin_owned_keys_still_reach_the_validator(self, manager):
+        args = self._validate_with(
+            manager, {"enabled": True, "vegas_mode": "scroll"})
+        assert args[0][0]["vegas_mode"] == "scroll"
+
+    def test_a_genuine_violation_is_still_reported(self, manager):
+        """Stripping core keys must not turn the check into a no-op."""
+        self._validate_with(
+            manager, {"enabled": True, "typo_key": 1},
+            valid=False, errors=["Field root: 'typo_key' was unexpected"])
+        manager._set_degraded_safe.assert_called()
+        reason = manager._set_degraded_safe.call_args[0][1]
+        assert reason and "typo_key" in reason