[Installer] Make the Inno Setup installer the default, with its failure hook.

COCKATRICE_WIN_INSTALLER now defaults to InnoSetup. NSIS stays selectable for
one release as the legacy fallback, and the two can still be built from one
tree and compared on a real upgrade.

The switches question from the previous commit is settled from Inno Setup's
source: the setup command line is an if/else-if chain over the switches it
knows, with no fallback that rejects the rest, so /R, /PID= and /D= are
ignored rather than refused. The client therefore sends one command line that
drives either installer:

- /R and /PID= for NSIS, which also needs /D= last and unquoted;
- /VERYSILENT and the CloseApplications set for Setup, which releases the
  mapped runtime DLLs through Restart Manager instead of waiting for a pid;
- /UPDATER as the client's own mark, read only by the Inno Setup script.

An older client that passes only the NSIS switches still installs; it walks
the wizard once instead of running silently.

The Sentry offer that AbortInstall carried is ported: a silent run the updater
launched, which began replacing files and never reached the end, offers to
send its log through the same helper. The helper is embedded with a [Files]
dontcopy entry and extracted at send time; a repeated [Files] section merges
with the generated one instead of being a compile error. Setup prefixes every
log line with a timestamp, so the helper's ABORT scan now allows that prefix.

CI installs Inno Setup next to NSIS, dumps ISCCOutput.log and the generated
script when the installer fails to compile, and --package NSIS|InnoSetup
selects the installer through the CMake option instead of adding a second
CPack generator to the run.

.github/workflows/desktop-build.yml

@@ -552,10 +552,13 @@ jobs:
           modules: ${{ matrix.qt_modules }}
           version: ${{ matrix.qt_version }}
 
-      - name: "[Windows] Install NSIS"
+      # Inno Setup writes the default Windows installer (COCKATRICE_WIN_INSTALLER=InnoSetup);
+      # NSIS stays installed because the option still selects the old installer, and CI has to
+      # be able to build both to compare them on a real upgrade.
+      - name: "[Windows] Install installer tooling"
         if: matrix.os == 'Windows'
         shell: bash
-        run: choco install nsis
+        run: choco install nsis innosetup
 
       # Ninja invokes cl.exe directly and needs the MSVC environment on PATH.
       - name: "[Windows] Set up MSVC environment"
@@ -745,16 +748,26 @@ jobs:
           # `debug-files upload` and DIFs are matched by debug ID, not release.
           sentry-cli debug-files upload --org cockatrice --project cockatrice-desktop "${paths[@]}"
 
-      # CPack reports a failed makensis run as "Problem running NSIS command"
-      # plus a path to NSISOutput.log, and that log lives only on the runner, so
-      # the actual compile error is otherwise nowhere in the workflow output.
-      # Dump it, or a broken installer script is undiagnosable from CI alone.
+      # CPack reports a failed installer compile only as a path to a log that lives on the
+      # runner: NSISOutput.log for makensis, ISCCOutput.log for Inno Setup's compiler. The
+      # Inno Setup error names a line of the script CPack generated, so that script is
+      # dumped too - without them a broken installer script is undiagnosable from CI alone.
       # shell: bash matters here - the default pwsh resolves `find` to Windows'
       # text-search find.exe, which errors instead of searching.
-      - name: "Dump NSIS compile log"
+      - name: "Dump installer compile log"
         if: failure() && matrix.os == 'Windows'
         shell: bash
-        run: find . -name NSISOutput.log -exec cat {} +
+        run: |
+          find . -name NSISOutput.log -o -name ISCCOutput.log | while read -r log; do
+            echo "::group::$log"
+            cat "$log"
+            echo "::endgroup::"
+          done
+          find . -path '*_CPack_Packages*' -name ISScript.iss | while read -r script; do
+            echo "::group::$script"
+            cat "$script"
+            echo "::endgroup::"
+          done
 
       # A master run hands over the archives it had to build itself so that
       # vcpkg-cache-import.yml, which runs in the default branch scope, can save them