Rename project from asr-v2 to speech

The project now covers both ASR and TTS, so "asr-v2" no longer fits.
Renames: quadlet (asr-v2.container -> speech.container, container
name, image tag), build.sh, FastAPI/UI title, and the OIDC env var
prefix (ASR_V2_* -> SPEECH_*, matching the renamed Authentik
provider/application slug "speech"). Internal Python packages
(asr/, tts/, core/) were already named generically and don't change.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

quadlet/speech.container

@@ -0,0 +1,25 @@
+[Unit]
+Description=Speech (ASR + TTS)
+After=network-online.target
+Wants=network-online.target
+
+[Container]
+ContainerName=speech
+Image=localhost/speech:latest
+Network=proxy
+User=983:983
+PublishPort=172.30.1.41:18101:8000
+Volume=/srv/asr/models-cache:/srv/asr/models-cache:z
+Volume=/srv/asr/uploads:/srv/asr/uploads:z
+Volume=/srv/asr/results:/srv/asr/results:z
+Volume=/srv/asr/custom-models:/srv/asr/custom-models:z
+EnvironmentFile=/srv/asr/env/asr.env
+AddDevice=nvidia.com/gpu=all
+HealthCmd=curl -sf http://127.0.0.1:8000/health
+
+[Service]
+Restart=always
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target