fix(packaging/deb): build the CLI the client .deb installs

With the client crates compiling again, deb got as far as "Build .debs" and died
on `install: No such file or directory` — a confusing way to report that
punktfunk-cli was never built.

Two halves of the same omission, from when the `punktfunk` CLI was added. deb.yml
pre-builds `-p punktfunk-client-linux -p punktfunk-client-session` and stops
there, while build-client-deb.sh installs THREE binaries. Its build-if-missing
guard tested only the first two, so the pre-built pair satisfied it, the fallback
build (which does list punktfunk-cli) was skipped, and the install of a binary
nobody had built failed.

deb.yml now builds all three, and the guard tests every binary it goes on to
install rather than a subset — either change alone fixes it; both together mean
the script is correct however it is called. That asymmetry is also why the arm64
leg passed throughout: it pre-builds nothing, so its guard always fired and built
all three.

arch was already right (`-p punktfunk-cli` in its PKGBUILD, installed at line 255)
and the rpm spec ships no CLI, so this was deb-only.

Verified: guard truth-tabled (skip when all three present, BUILD when the CLI is
missing, BUILD when nothing is), shellcheck clean, and punktfunk-cli builds to
target/release/punktfunk on a real Linux box.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

packaging/debian/build-client-deb.sh

@@ -40,8 +40,13 @@ BIN="$OUTDIR/$PKG"
 SESSION_BIN="$OUTDIR/punktfunk-session"
 # The headless CLI (design/client-architecture-split.md §4) ships with every client.
 CLI_BIN="$OUTDIR/punktfunk"
-if [ ! -x "$BIN" ] || [ ! -x "$SESSION_BIN" ]; then
-  echo "==> building $CRATE + punktfunk-client-session (release${TARGET:+ for $TARGET})"
+# Test every binary this script goes on to install, not a subset. It used to check only $BIN and
+# $SESSION_BIN while installing three, so a caller that pre-built exactly those two (deb.yml did)
+# satisfied the guard, skipped this build, and then died on `install: No such file or directory`
+# for $CLI_BIN — a confusing way to say "the CLI was never built". The arm64 leg never hit it
+# because it pre-builds nothing, so the guard always fired there and built all three.
+if [ ! -x "$BIN" ] || [ ! -x "$SESSION_BIN" ] || [ ! -x "$CLI_BIN" ]; then
+  echo "==> building $CRATE + punktfunk-client-session + punktfunk-cli (release${TARGET:+ for $TARGET})"
   cargo build --release --locked "${CARGO_TARGET_ARGS[@]}" -p "$CRATE" -p punktfunk-client-session -p punktfunk-cli
 fi