Switch to .pkg/.exe/.deb installers with Azure Trusted Signing

Replaces the zip-based ci/build.sh flow with installer outputs (Inno Setup
on Windows, productbuild on macOS, cpack DEB on Linux) signed via Microsoft
Trusted Signing on Windows and Apple Developer ID on macOS.

Plugin code: factory wavetables and presets now ship as files via the
installer rather than embedded BinaryData. PluginProcessor implements
getProgramDirectory/getFactoryProgramDirectories so gin scans factory
content from systemResourceRoot. First-run migration copies any presets
from the legacy com.socalabs/Wavetable/programs path into the new user
dir under Library/Audio/Presets/SocaLabs/Wavetable.

Bumps gin submodule to match Identity for getFactoryProgramDirectories
support.

Installer/macOS/distribution.xml

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="utf-8"?>
+<installer-gui-script minSpecVersion="2">
+    <title>Wavetable</title>
+    <organization>com.socalabs</organization>
+    <domains enable_anywhere="false" enable_currentUserHome="false" enable_localSystem="true"/>
+    <options customize="always" require-scripts="false" rootVolumeOnly="true"/>
+    <license file="EULA.rtf"/>
+    <welcome    file="welcome.txt"   mime-type="text/plain"/>
+
+    <choices-outline>
+        <line choice="com.socalabs.wavetable.vst"/>
+        <line choice="com.socalabs.wavetable.vst3"/>
+        <line choice="com.socalabs.wavetable.au"/>
+        <line choice="com.socalabs.wavetable.clap"/>
+        <line choice="com.socalabs.wavetable.resources"/>
+    </choices-outline>
+
+    <choice id="com.socalabs.wavetable.vst"
+            title="VST"
+            description="Install the VST plug-in to /Library/Audio/Plug-Ins/VST"
+            visible="true">
+        <pkg-ref id="com.socalabs.wavetable.vst.pkg"/>
+    </choice>
+
+    <choice id="com.socalabs.wavetable.vst3"
+            title="VST3"
+            description="Install the VST3 plug-in to /Library/Audio/Plug-Ins/VST3"
+            visible="true">
+        <pkg-ref id="com.socalabs.wavetable.vst3.pkg"/>
+    </choice>
+
+    <choice id="com.socalabs.wavetable.au"
+            title="Audio Unit"
+            description="Install the Audio Unit plug-in to /Library/Audio/Plug-Ins/Components"
+            visible="true">
+        <pkg-ref id="com.socalabs.wavetable.au.pkg"/>
+    </choice>
+
+    <choice id="com.socalabs.wavetable.clap"
+            title="CLAP"
+            description="Install the CLAP plug-in to /Library/Audio/Plug-Ins/CLAP"
+            visible="true">
+        <pkg-ref id="com.socalabs.wavetable.clap.pkg"/>
+    </choice>
+
+    <choice id="com.socalabs.wavetable.resources"
+            title="Factory Wavetables &amp; Presets"
+            description="Install factory content to /Library/Audio/Presets/SocaLabs/Wavetable"
+            visible="true"
+            enabled="false"
+            selected="true">
+        <pkg-ref id="com.socalabs.wavetable.resources.pkg"/>
+    </choice>
+
+    <pkg-ref id="com.socalabs.wavetable.vst.pkg"       version="0">vst.pkg</pkg-ref>
+    <pkg-ref id="com.socalabs.wavetable.vst3.pkg"      version="0">vst3.pkg</pkg-ref>
+    <pkg-ref id="com.socalabs.wavetable.au.pkg"        version="0">au.pkg</pkg-ref>
+    <pkg-ref id="com.socalabs.wavetable.clap.pkg"      version="0">clap.pkg</pkg-ref>
+    <pkg-ref id="com.socalabs.wavetable.resources.pkg" version="0">resources.pkg</pkg-ref>
+</installer-gui-script>

Installer/macOS/scripts/postinstall

@@ -0,0 +1,6 @@
+#!/bin/sh
+# Force the AU host registrar to rescan so the freshly installed Component is
+# visible without a logout/reboot.
+killall -9 AudioComponentRegistrar >/dev/null 2>&1
+
+exit 0

Installer/macOS/scripts/preinstall

@@ -0,0 +1,14 @@
+#!/bin/sh
+# Remove any prior install of Wavetable so the new bundle takes its place cleanly.
+
+rm -Rf "/Library/Audio/Plug-Ins/VST/Wavetable.vst"
+rm -Rf "/Library/Audio/Plug-Ins/VST3/Wavetable.vst3"
+rm -Rf "/Library/Audio/Plug-Ins/Components/Wavetable.component"
+rm -Rf "/Library/Audio/Plug-Ins/CLAP/Wavetable.clap"
+
+# Wipe the previous shipped factory content so removed wavetables/presets from
+# the old version don't linger. User content lives under ~/Library and is left alone.
+rm -Rf "/Library/Audio/Presets/SocaLabs/Wavetable/Presets"
+rm -Rf "/Library/Audio/Presets/SocaLabs/Wavetable/Wavetables"
+
+exit 0

Installer/macOS/welcome.txt

@@ -0,0 +1,17 @@
+Wavetable by SocaLabs
+=====================
+
+This installer places the Wavetable plug-in in your system audio plug-in
+folders along with the factory wavetable bank and factory presets.
+
+Components:
+  • VST                  /Library/Audio/Plug-Ins/VST
+  • VST3                 /Library/Audio/Plug-Ins/VST3
+  • Audio Unit           /Library/Audio/Plug-Ins/Components
+  • CLAP                 /Library/Audio/Plug-Ins/CLAP
+  • Factory content      /Library/Audio/Presets/SocaLabs/Wavetable
+
+User-saved presets live under
+  ~/Library/Audio/Presets/SocaLabs/Wavetable
+
+and are not touched by this installer.