build: add single-command release script + portable zip artifacts

One-developer workflow: ``python build/make_release.py`` on each
target OS produces both the installer and a portable .zip for that
platform. Preflight checks PyInstaller / Pillow / iscc / hdiutil /
ditto / appimagetool and bails with install hints if anything is
missing — no half-built dist/.

New scripts:
- build/make_release.py   — orchestrator, auto-detects host OS.
- build/generate_icons.py — icon.ico / icon.icns / icon.png from
  src/gui/assets/datatools_icon_256.png (Pillow ships ICO + ICNS
  writers; no platform tooling needed).
- build/build_portable_zip.py — Win/Linux portable zip via stdlib.
- build/macos/build_zip.sh — Mac portable .app via ditto so
  bundle metadata survives.

installer.iss now adds: Quick Launch task (opt-in, legacy Win 7),
App Paths registry entry (Win+R "DataTools" works), SetupIconFile,
UninstallDisplayIcon, AppSupportURL, AppUpdatesURL.

CI workflow uploads installer + portable per platform and attaches
both to GitHub Releases on tag push.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

build/installer.iss

@@ -1,11 +1,26 @@
 ; Inno Setup script for DataTools — Windows installer.
 ;
 ; Compile from the repo root:
-;   iscc /DAppVersion=1.0.0 build\installer.iss
+;   iscc /DAppVersion=3.0 build\installer.iss
 ;
 ; CI passes the version via /DAppVersion to keep src/__init__.py the
 ; single source of truth. Local manual builds: pass /DAppVersion or
 ; let the default kick in.
+;
+; What this installer wires up (covers the "easy launch" surface):
+;   * Start Menu group:  Start → DataTools → DataTools / Uninstall
+;   * Desktop shortcut:  optional, checked by default during install
+;   * Quick Launch:      optional, off by default (legacy Win 7 + power
+;                        users who keep the bar enabled). Windows 10/11
+;                        users pin to taskbar manually via right-click —
+;                        OS security policy forbids programmatic pinning.
+;   * App Paths entry:   so ``DataTools`` typed into Win+R / cmd works.
+;
+; Self-contained: the installer contains a frozen PyInstaller bundle
+; (Python + every runtime dep). No pre-install or post-install steps
+; on the buyer's machine. UAC is NOT required because we install
+; per-user by default; the prompt only fires if the buyer asks for an
+; all-users install.
 
 #ifndef AppVersion
   #define AppVersion "0.0.0-dev"
@@ -18,11 +33,15 @@ AppVersion={#AppVersion}
 AppVerName=DataTools {#AppVersion}
 AppPublisher=DataTools
 AppPublisherURL=https://datatools.app
+AppSupportURL=https://datatools.app/support
+AppUpdatesURL=https://datatools.app/releases
 DefaultDirName={autopf}\DataTools
 DefaultGroupName=DataTools
 DisableProgramGroupPage=yes
 OutputDir=..\dist
 OutputBaseFilename=DataTools-{#AppVersion}-win-setup
+SetupIconFile=icon.ico
+UninstallDisplayIcon={app}\DataTools.exe
 Compression=lzma2/max
 SolidCompression=yes
 WizardStyle=modern
@@ -30,20 +49,37 @@ ArchitecturesInstallIn64BitMode=x64
 PrivilegesRequired=lowest
 PrivilegesRequiredOverridesAllowed=dialog
 ; Allow per-user install (no UAC prompt) when admin isn't available.
+; Buyers without admin rights can still install without IT involvement.
+
+ChangesAssociations=no
+CloseApplications=force
+RestartApplications=no
 
 [Languages]
 Name: "english"; MessagesFile: "compiler:Default.isl"
 
 [Tasks]
 Name: "desktopicon"; Description: "Create a &desktop shortcut"; GroupDescription: "Additional shortcuts:"
+Name: "quicklaunchicon"; Description: "Create a &Quick Launch shortcut"; GroupDescription: "Additional shortcuts:"; Flags: unchecked; OnlyBelowVersion: 6.1
 
 [Files]
 Source: "..\dist\DataTools\*"; DestDir: "{app}"; Flags: recursesubdirs ignoreversion
 
 [Icons]
-Name: "{group}\DataTools"; Filename: "{app}\DataTools.exe"
+; Start Menu entries — created unconditionally so the app is always
+; discoverable via Start search.
+Name: "{group}\DataTools"; Filename: "{app}\DataTools.exe"; IconFilename: "{app}\DataTools.exe"
 Name: "{group}\Uninstall DataTools"; Filename: "{uninstallexe}"
-Name: "{autodesktop}\DataTools"; Filename: "{app}\DataTools.exe"; Tasks: desktopicon
+; Desktop shortcut — opt-in via the Tasks page.
+Name: "{autodesktop}\DataTools"; Filename: "{app}\DataTools.exe"; IconFilename: "{app}\DataTools.exe"; Tasks: desktopicon
+; Quick Launch (legacy) — only relevant on Win 7 and older.
+Name: "{userappdata}\Microsoft\Internet Explorer\Quick Launch\DataTools"; Filename: "{app}\DataTools.exe"; IconFilename: "{app}\DataTools.exe"; Tasks: quicklaunchicon
+
+[Registry]
+; App Paths — lets the buyer launch from Win+R or cmd with just
+; "DataTools" instead of a full path. Per-user hive so the per-user
+; install path doesn't need admin to register.
+Root: HKCU; Subkey: "Software\Microsoft\Windows\CurrentVersion\App Paths\DataTools.exe"; ValueType: string; ValueName: ""; ValueData: "{app}\DataTools.exe"; Flags: uninsdeletekey
 
 [Run]
 Filename: "{app}\DataTools.exe"; Description: "Launch DataTools"; Flags: nowait postinstall skipifsilent