Add Navidrome Scrobbled scrobbler plugin

A Python Extism plugin for Navidrome that scrobbles playback to a
self-hosted Scrobbled (Last.fm-compatible) server, plus Gitea Actions
CI that lints, tests, builds/validates, and publishes the .ndp
artifact to pkgs.daubney.dev.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018n5ffHCn5QUjpDtuWTk3fh

Makefile

@@ -0,0 +1,25 @@
+PLUGIN_ID = navidrome-scrobbled
+WASM_FILE = dist/plugin.wasm
+NDP_FILE = dist/$(PLUGIN_ID).ndp
+
+.PHONY: build package validate test clean
+
+build: $(WASM_FILE)
+
+$(WASM_FILE): plugin/__init__.py
+	mkdir -p dist
+	extism-py plugin/__init__.py -o $(WASM_FILE)
+
+package: $(NDP_FILE)
+
+$(NDP_FILE): $(WASM_FILE) manifest.json
+	zip -j $(NDP_FILE) manifest.json $(WASM_FILE)
+
+validate: package
+	navidrome plugin validate $(NDP_FILE)
+
+test:
+	python3 -m unittest discover -s tests -v
+
+clean:
+	rm -rf dist