desktop: one name across all three install channels (issue 2075)

The app answered to three different names depending on how it arrived, and the
part that actually hurt was WM_CLASS. Reading tauri-bundler settles what it is:
the generated .desktop template writes StartupWMClass={{exec}} where exec is
main_binary_name, and tao creates its GtkApplication with a NULL app id
(enableGTKAppId defaults off), so GTK falls back to the program name. WM_CLASS
is the binary name, nothing else.

Which inverts this issue's premise. The rename could not break grouping,
because two channels weren't grouping in the first place: pacman ships
/usr/bin/thoughtsync and the AppImage's AppRun execs thoughtsync-desktop, while
all three hand-written entries hardcoded StartupWMClass=ThoughtSync — a string
no binary in any channel has ever reported. Only the .deb worked, and only
because Tauri generates its entry from the binary and never consulted us.

So: thoughtsync everywhere, carried by the build target itself via Cargo [[bin]]
plus mainBinaryName rather than by the install path, since the target name is
what the desktop reads. The pacman package sheds its -desktop suffix and
declares conflict+replaces so an upgrade retires the old one instead of landing
beside it and fighting over /usr/bin/thoughtsync.

The .deb verifier now asserts binary path, Exec and StartupWMClass all agree,
which is the part that keeps this fixed: the .deb's entry is the one no human
writes, so it's the one that drifts silently.

Package: thought-sync stays. tauri-bundler derives it as kebab-case(productName)
with no override, and rewriting a control archive on every build is a poor trade
for one uninstall command.

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

desktop/packaging/deb/verify.sh

@@ -10,20 +10,25 @@
 # that installs and then won't launch because a library it needs was never
 # declared.
 #
-# Four checks, cheapest first:
+# Five checks, cheapest first:
 #   1. Print the control file + contents — the generated metadata becomes ground
 #      truth in the build log instead of an assumption.
-#   2. dpkg-shlibdeps: the canonical Debian answer for "what does this ELF
+#   2. Naming: the binary is /usr/bin/thoughtsync and the generated .desktop
+#      entry's StartupWMClass matches it. The app used to identify itself three
+#      different ways depending on install channel (issue 2075); this is what
+#      keeps the .deb — the only channel whose entry Tauri generates for us —
+#      from drifting away from the two we write by hand.
+#   3. dpkg-shlibdeps: the canonical Debian answer for "what does this ELF
 #      actually need". Compared against what the package declares.
-#   3. Every declared dependency resolves to a real package in apt (catches a
+#   4. Every declared dependency resolves to a real package in apt (catches a
 #      typo in the hand-written list, which would break install for everyone).
-#   4. If a docker CLI is present, install into a clean debian container — the
+#   5. If a docker CLI is present, install into a clean debian container — the
 #      highest-fidelity check, since the build image already has the -dev
 #      packages installed and so can't prove resolution on its own.
 #
-# Check 4 is opportunistic on purpose: the build image is not guaranteed to carry
+# Check 5 is opportunistic on purpose: the build image is not guaranteed to carry
 # a docker CLI, and adding one at job time would violate "the image is the
-# toolchain" (rule 5). Checks 1-3 are self-contained and always run.
+# toolchain" (rule 5). Checks 1-4 are self-contained and always run.
 set -euo pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
@@ -63,7 +68,41 @@ BIN="$(find "$WORK/root" -type f -path '*/bin/*' -print -quit)"
 [ -n "$BIN" ] || { echo "ERROR: no binary found under */bin/ in the package" >&2; exit 1; }
 echo "    (binary: ${BIN#"$WORK/root"})"
 
-# --- 2. what the ELF actually needs -----------------------------------------
+# --- 2. naming is consistent -------------------------------------------------
+# CANON is the one name the app answers to everywhere: the binary, the CLI
+# command, the icon, and the WM_CLASS the window reports. Hardcoded here on
+# purpose — this literal IS the contract the three install channels are held to.
+# Deliberately NOT asserted: the control file's `Package:` field, which is
+# `thought-sync`. tauri-bundler derives it as kebab-case(productName) with no
+# config override, so "ThoughtSync" splits at the hump. Fixing it would mean
+# unpacking and rewriting the control archive on every build — a fragile step for
+# a cosmetic gain on one uninstall command. Left as a known wart (issue 2075).
+CANON="thoughtsync"
+
+installed_bin="${BIN#"$WORK/root"}"
+[ "$installed_bin" = "/usr/bin/$CANON" ] ||
+  note_fail "binary is at $installed_bin, expected /usr/bin/$CANON (mainBinaryName in tauri.conf.json)."
+
+# Tauri generates this entry from the binary name, so a mismatch means the config
+# and the bundler have diverged — exactly the drift that made the app group under
+# a different taskbar icon depending on how it was installed.
+entry="$(find "$WORK/root/usr/share/applications" -name '*.desktop' -print -quit 2>/dev/null || true)"
+if [ -z "$entry" ]; then
+  note_fail "no .desktop entry in the package — the app would not appear in any menu."
+else
+  echo "--- desktop entry ($(basename "$entry")) ---"
+  sed 's/^/    /' "$entry"
+  wmclass="$(sed -n 's/^StartupWMClass=//p' "$entry" | head -1)"
+  [ "$wmclass" = "$CANON" ] ||
+    note_fail "StartupWMClass is '${wmclass:-<unset>}', expected '$CANON' — the taskbar icon will not group."
+  # `%u`/`%U` field codes may follow, so match the first word only.
+  exec_cmd="$(sed -n 's/^Exec=//p' "$entry" | head -1 | awk '{print $1}')"
+  [ "$exec_cmd" = "$CANON" ] ||
+    note_fail "Exec runs '${exec_cmd:-<unset>}', expected '$CANON'."
+fi
+[ "$fail" -eq 0 ] && echo "OK: binary, Exec and StartupWMClass all agree on '$CANON'."
+
+# --- 3. what the ELF actually needs -----------------------------------------
 if command -v dpkg-shlibdeps >/dev/null 2>&1; then
   # dpkg-shlibdeps insists on a debian/control in the working directory even with
   # -O (write to stdout); a stub is enough to let it do the ELF analysis.
@@ -110,7 +149,7 @@ else
   echo "WARN: dpkg-shlibdeps unavailable — skipping the ELF dependency check." >&2
 fi
 
-# --- 3. declared deps are real packages -------------------------------------
+# --- 4. declared deps are real packages -------------------------------------
 if apt-cache policy dpkg >/dev/null 2>&1 && [ -n "$(apt-cache policy dpkg 2>/dev/null)" ]; then
   for pkg in $declared; do
     if [ -z "$(apt-cache policy "$pkg" 2>/dev/null)" ]; then
@@ -120,7 +159,7 @@ if apt-cache policy dpkg >/dev/null 2>&1 && [ -n "$(apt-cache policy dpkg 2>/dev
   [ "$fail" -eq 0 ] && echo "OK: every declared dependency exists in apt."
 fi
 
-# --- 4. clean-container install (opportunistic) -----------------------------
+# --- 5. clean-container install (opportunistic) -----------------------------
 # The build image already has libwebkit2gtk-4.1-dev etc. installed, so installing
 # here would pass no matter what we declared. Only a pristine container proves
 # apt can actually resolve the package for a real user.