Songr 1.2.0

This release fixes every open GitHub issue and smooths out Docker onboarding.

Fixed

#5 — Play icon off-center. Transport icons (play/pause/skip) are now
inline SVGs instead of font glyphs, so they render centered everywhere.
#6 — Album back button said "Artists". The back button on an album page
is now labeled with the artist you navigated from.
#7 — Cannot add to queue. Album actions (queue, play next, etc.) now
execute against the same hierarchy that resolved the item, so they no
longer silently fail.
#8 — Default zone. Pinning a zone now sticks: reconnects and zone-list
refreshes no longer clobber your pinned default zone.
#9 — Volume control shifts while adjusting. The volume readout reserves
a fixed width, so digit changes can't move the slider under your pointer.
#10 — "Go to album" / "Go to artist" from the playback bar. These now
resolve through the library's catalog identity and land on the correct
album/artist pages.
Fast-typing fix: typing a letter and immediately pressing Space in the
library search palette no longer toggles playback.

docker compose up now works without a .env file — env_file is
optional (requires Compose v2.24+), and the obsolete version: key is
gone.
The README documents a docker run --network host one-liner for the
published image.

Docker image: ghcr.io/roethlar/songr:v1.2.0 (also :latest).