feat(packaging): Fedora/Bazzite packaging — COPR RPM, bootc image, gamescope-default config

Roadmap #3 (install on other devices). Bazzite already ships gamescope + PipeWire + the
NVIDIA stack, so the host slots in with minimal new deps (ffmpeg-libs from RPM Fusion + opus
+ libei).

- packaging/rpm/punktfunk.spec — builds punktfunk-host from source (cargo), installs the
  binary + udev rule + systemd user unit + headless helpers; Requires/Recommends mapped from
  the Ubuntu bootstrap deps to Fedora.
- packaging/bootc/Containerfile — layer punktfunk into a bazzite-nvidia bootc image for
  atomic, image-based installs.
- packaging/bazzite/host.env — gamescope-default appliance config (spawned per session).
- packaging/copr/ + packaging/README.md — COPR build-from-SCM settings + install docs
  (rpm-ostree and bootc paths), and why not Flatpak.
- LICENSE-MIT + LICENSE-APACHE — materialize the declared `MIT OR Apache-2.0` (was unfiled);
  the RPM ships them.

Not buildable on the Ubuntu dev box (no rpm tooling) — the COPR/Fedora build is operator-run;
all spec-referenced files verified present and the cargo build is green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packaging/bazzite/host.env

@@ -0,0 +1,26 @@
+# punktfunk host config for Bazzite (~/.config/punktfunk/host.env).
+#
+# Bazzite ships gamescope, PipeWire and the NVIDIA driver, so the default backend here is
+# gamescope: the host spawns a headless gamescope per session at the client's exact mode and
+# captures its PipeWire node — no separate desktop session to bring up. Set PUNKTFUNK_GAMESCOPE_APP
+# to what you want to run inside it (e.g. `steam -gamepadui` for a SteamOS-like couch session).
+
+XDG_RUNTIME_DIR=/run/user/1000
+DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
+
+# gamescope backend: spawned per session, no compositor login required.
+PUNKTFUNK_COMPOSITOR=gamescope
+PUNKTFUNK_VIDEO_SOURCE=virtual
+PUNKTFUNK_GAMESCOPE_APP=steam -gamepadui
+
+# gamescope hosts its own EIS input socket — input lands in the nested session.
+PUNKTFUNK_INPUT_BACKEND=gamescope
+
+# GPU zero-copy capture (dmabuf -> CUDA -> NVENC). Auto-falls back to CPU if unavailable.
+PUNKTFUNK_ZEROCOPY=1
+
+#RUST_LOG=info
+
+# To drive the full Plasma/GNOME desktop instead of a nested gamescope, switch to:
+#   PUNKTFUNK_COMPOSITOR=kwin    (and run inside a KDE session — WAYLAND_DISPLAY/XDG_CURRENT_DESKTOP set)
+#   PUNKTFUNK_INPUT_BACKEND=libei