Fix PROMPT_COMMAND collision with zoxide causing ';;' parse error

v1.14.19c installed 'history -a; ' at the start of PROMPT_COMMAND
before zoxide's init ran. Zoxide's init uses ';' as its separator
when prepending __zoxide_hook, producing 'history -a;;__zoxide_hook'.
Every interactive prompt then emitted:

  bash: PROMPT_COMMAND: syntax error near unexpected token ';;'

History flushing still worked (the 'history -a' half parsed fine),
but the error spam made the shell feel broken.

Fix by moving the history-flush PROMPT_COMMAND assignment AFTER
zoxide's init, and using a newline separator (via ${PROMPT_COMMAND:+...}
parameter expansion) so there's no semicolon involved at all. Each
PROMPT_COMMAND line runs as its own statement, no parsing contention.

Known upstream issue: https://github.com/ajeetdsouza/zoxide/issues/722

rootfs/home/developer/.bash_aliases

@@ -16,12 +16,11 @@ export HISTCONTROL=ignoreboth:erasedups
 export HISTTIMEFORMAT='%F %T  '
 shopt -s histappend 2>/dev/null
 shopt -s cmdhist 2>/dev/null
-# Flush every command to disk immediately so reboots don't lose recent work.
-# Guarded so repeated sourcing (e.g. `exec bash`) doesn't stack duplicates.
-if [ -z "${DEVBOX_HIST_SET:-}" ]; then
-  PROMPT_COMMAND="history -a; ${PROMPT_COMMAND:-}"
-  export DEVBOX_HIST_SET=1
-fi
+# Note: PROMPT_COMMAND="history -a" is installed LATER in this file,
+# after zoxide's init runs. Installing it here would create a
+# "history -a;;__zoxide_hook" chain because zoxide's init uses ';'
+# as its separator and prepends itself; two adjacent ';' breaks the
+# parser. See https://github.com/ajeetdsouza/zoxide/issues/722.
 
 # ── Common aliases ───────────────────────────────────────────────────
 # Prefer eza (modern ls) when available
@@ -65,6 +64,16 @@ if command -v fzf >/dev/null 2>&1; then
   eval "$(fzf --bash)" 2>/dev/null || true
 fi
 
+# ── PROMPT_COMMAND: flush history every prompt ───────────────────────
+# Installed AFTER zoxide init so zoxide's hook is already in place;
+# we append with a newline separator to avoid the ';;' parse error
+# described at the top of this file. Guarded so repeated sourcing
+# (e.g. `exec bash`) doesn't stack duplicates.
+if [ -z "${DEVBOX_HIST_SET:-}" ]; then
+  PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND$'\n'}history -a"
+  export DEVBOX_HIST_SET=1
+fi
+
 # ── Prompt: show [opencode-devbox] tag so it's obvious you're in the container
 # Preserves the default Debian PS1 logic but prefixes with a container marker.
 if [ -n "${PS1:-}" ] && [ -z "${DEVBOX_PS1_SET:-}" ]; then