feat(server): INGEST_WING_ROUTING wires the Router; remove the classifier path (#208)

Removes the LLM classifier, the substring 'BM25' scorer, the agreement gate,
the backtest and the old migrate/wingmigrate tooling: measured at 2 of 55
pages placed (#208), and the migration was built for the per-wing facts layout
this branch replaces. wing now holds the decision types, the Router and
KnownWings. INGEST_WING_ROUTING=1 builds the Router (default wing
INGEST_DEFAULT_WING=web-clip, client pattern from INGEST_CLIENT_BLOCK or
CLAUDE_INGEST_CLIENT_BLOCK); a bad default or pattern is fatal at startup.
Watcher tests rewritten for the Router, including a deliberate subfolder into
any existing wing, typo'd folders parked, forged-key and edit-while-placing
cases.

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

ingestion/internal/wing/router_test.go

@@ -85,3 +85,30 @@ func TestRouter_ANameThatIsNotPlainIsRefusedAsSuch(t *testing.T) {
 		})
 	}
 }
+
+func TestNewRouter(t *testing.T) {
+	dir := routerBrain(t)
+	t.Run("valid", func(t *testing.T) {
+		r, err := wing.NewRouter(dir, "web-clip", "acme-client|globex")
+		assert.NoError(t, err)
+		d := r.Resolve(context.Background(), wing.Note{Text: "kickoff with GLOBEX"})
+		assert.Equal(t, wing.Exception, d.Source, "the marker is matched case-insensitively")
+	})
+	t.Run("no marker pattern means no content check", func(t *testing.T) {
+		r, err := wing.NewRouter(dir, "web-clip", "")
+		assert.NoError(t, err)
+		assert.Equal(t, wing.Default, r.Resolve(context.Background(), wing.Note{Text: "anything"}).Source)
+	})
+	t.Run("a default that is not a plain wing name is a startup error", func(t *testing.T) {
+		_, err := wing.NewRouter(dir, "Web Clip", "")
+		assert.Error(t, err)
+	})
+	t.Run("an empty default is a startup error", func(t *testing.T) {
+		_, err := wing.NewRouter(dir, "", "")
+		assert.Error(t, err)
+	})
+	t.Run("a pattern that does not compile is a startup error", func(t *testing.T) {
+		_, err := wing.NewRouter(dir, "web-clip", "([unclosed")
+		assert.Error(t, err, "a client filter that silently does nothing is worse than none")
+	})
+}