fix(flatpakrepo): add RuntimeRepo so the runtime resolves without Flathub

A fresh system (e.g. Ubuntu after apt install flatpak) has no Flathub
remote, so installing from the .flatpakrepo could not find the
freedesktop 25.08 runtime. Found in the HeiniRemote VM test 2026-10-13.

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

.gitea/workflows/build-flatpak.yml

@@ -152,6 +152,7 @@ jobs:
           [Flatpak Repo]
           Title=HeiniRemote Agent
           Url=$BASE
+          RuntimeRepo=https://dl.flathub.org/repo/flathub.flatpakrepo
           Homepage=https://pc-heini.de/
           Comment=HeiniRemote remote maintenance agent as a Flatpak
           Description=Install the HeiniRemote agent on any Linux distribution via Flatpak.

README.md

@@ -61,7 +61,7 @@ user unit wrapping `flatpak run`:
 ```ini
 # ~/.config/systemd/user/heiniremote-agent.service
 [Unit]
-Description=HeiniRemote agent (Flatpak)
+Description=PC-Heini Fernwartung (HeiniRemote Agent, Flatpak)
 After=graphical-session.target
 
 [Service]
@@ -100,3 +100,5 @@ StatusNotifier names for the tray icon.
 | `heiniremote-wrapper.sh` | Entry point: host-shell `$SHELL` override + config adoption. |
 | `host-shell.sh` | `flatpak-spawn --host` bridge for the PTY console. |
 | `de.pc_heini.HeiniRemoteAgent.*` | Desktop file, AppStream metainfo (version stamped by CI), icon. |
+
+Builds track the newest upstream `main` commit. To rebuild before the nightly check, push a change to a packaging file (README, docs, LICENSE and .gitignore are ignored by the workflow) or run the workflow manually via `workflow_dispatch`.

heiniremote.flatpakrepo

@@ -4,6 +4,9 @@ Title=HeiniRemote Agent
 # so the canonical copy to use is:
 #   https://git.pc-heini.de/pc-heini/HeiniRemote-AgentFlatpak/raw/branch/pages/heiniremote.flatpakrepo
 Url=https://git.pc-heini.de/pc-heini/HeiniRemote-AgentFlatpak/raw/branch/pages
+# Lets `flatpak install` pull the freedesktop runtime on a system that has no
+# Flathub remote yet (e.g. a fresh Ubuntu after `apt install flatpak`).
+RuntimeRepo=https://dl.flathub.org/repo/flathub.flatpakrepo
 Homepage=https://pc-heini.de/
 Comment=HeiniRemote remote maintenance agent as a Flatpak
 Description=Install the HeiniRemote agent on any Linux distribution via Flatpak.

host-shell.sh

@@ -9,9 +9,21 @@
 # The inner resolution runs ON THE HOST: flatpak-spawn forwards the sandbox
 # environment, so $SHELL would still point at this script — resolve the user's
 # real login shell from passwd instead and fix up $SHELL before exec'ing it.
-exec flatpak-spawn --host /bin/sh -c '
+#
+# The PTY itself was allocated inside the sandbox (its own devpts instance),
+# so on the host the forwarded fd cannot be named (`tty` fails, no
+# controlling terminal, tools that open /dev/tty break). script(1) allocates a
+# second, host-side PTY for the shell and relays through the forwarded one;
+# util-linux >= 2.35 also passes window-size changes along.
+# flatpak-spawn --host does not forward the caller's environment: without
+# --env the host shell starts with no TERM at all (login scripts then fail
+# in tput and in integer tests on the empty LINES/COLUMNS).
+exec flatpak-spawn --host --env=TERM="${TERM:-xterm-256color}" --env=COLORTERM=truecolor /bin/sh -c '
     shell="$(getent passwd "$(id -un)" | cut -d: -f7)"
     [ -x "$shell" ] || shell=/bin/sh
     export SHELL="$shell"
+    if command -v script >/dev/null 2>&1; then
+        exec script -q -e -c "exec \"$shell\" -l" /dev/null
+    fi
     exec "$shell" -l
 '

scripts/make-flatpak.sh

@@ -72,3 +72,5 @@ flatpak build-export --disable-sandbox repo build-dir "$BRANCH"
 flatpak build-update-repo repo --title="HeiniRemote Agent" --prune --prune-depth=1
 
 echo ">> done: ./repo"
+
+# Touched to trigger a rebuild against upstream f8c509b (2026-09-21).