[itomek]

Changes

• NSIS (installer/nsis/installer.nsh): customInstall macro now embeds lemonade-server-minimal.msi into \$PLUGINSDIR (auto-cleaned on exit) and runs msiexec /i ... /qn /norestart. Exit codes 0/1638/3010 are logged as success; any other code is logged via DetailPrint but the GAIA install is never aborted. Includes LogicLib.nsh and the generated installer/version.nsh at file scope (using \${BUILD_RESOURCES_DIR} since electron-builder runs makensis from a temp directory).
• CI (.github/workflows/build-installers.yml): three new Windows-only steps — generate installer/version.nsh from src/gaia/version.py, download the pinned Lemonade MSI from GitHub Releases (version parsed via shell grep; size sanity-checked ≥50MB), and post-build verify-bundled step that is warn-only when 7z can't list (NSIS solid compression) and only fails when 7z succeeds but the MSI is absent. src/gaia/version.py added to the path filter so CI re-runs when LEMONADE_VERSION is bumped.
• Tests: TestEnsureLemonadeInstalledSkipsWhenPresent (4 cases: target / newer / older-above-min / older-below-min) and TestLegacyFallback lock in gaia init's skip-when-installed behavior for AC4/AC5. TestLemonadeProductCodeUninstall verifies --purge-lemonade uses registry-based msiexec /x {ProductCode} regardless of install origin (AC6).
• Drive-by Linux fix (src/gaia/installer/lemonade_installer.py): _uninstall_linux was calling apt remove lemonade but the v10.0.0+ DEB installs as lemonade-server. Found via live end-to-end testing on Ubuntu 24.04; fixed in a separate commit.
• .gitignore: ignore installer/lemonade-server-minimal.msi (downloaded at build time, never committed).

Why

Issue #774: first-run on a fresh Windows machine should install Lemonade Server automatically so users don't hit "Lemonade not found" on first gaia chat. Keeps MSI out of the repo (downloaded per-build from upstream, pinned to LEMONADE_VERSION), uses \$PLUGINSDIR so the 150MB MSI doesn't persist on disk, and keeps GAIA install robust when Lemonade install misbehaves (graceful failure, not abort).

Acceptance criteria verified on Ubuntu 24.04

AC	Status
AC1 — fresh gaia init installs Lemonade v10.0.0	✅ DEB downloaded, lemonade-server version 10.0.0
AC4 — second gaia init detects v10.0.0 and skips	✅ "Lemonade Server found: v10.0.0 / Version is compatible"
AC6 — gaia uninstall --purge --purge-lemonade --yes removes Lemonade	✅ "uninstalled via LemonadeInstaller"; lemonade-server no longer on PATH
Unit tests 105/105	✅
Lint (black, isort, pylint, flake8, import validation, doc version)	✅ all pass

Still to verify (joint Windows session)

• AC2 — built .exe embeds lemonade-server-minimal.msi
• AC3 — silent install produces lemonade-server --version → 10.0.0 on PATH
• AC5 — already-newer Lemonade: MSI returns 1638 and GAIA continues (visible DetailPrint)
• msiexec /x {ProductCode} uninstall path end-to-end on Windows

Notes for reviewers

• The post-build 7z check is intentionally warn-only when 7z l itself fails — NSIS solid compression can prevent entry listing, which would otherwise produce false-negative CI failures. Compile-time guarantee is the NSIS File directive: if the MSI wasn't present at build time, makensis would have aborted the build.
• \${BUILD_RESOURCES_DIR} is the right include path, not a bare relative path. electron-builder runs makensis from a generated temp directory, so bare installer\version.nsh would fail to resolve — this macro is what the existing File directive also uses and is documented in electron-builder's NsisTarget.
• No Python production code changes were needed for the skip-when-installed behavior — _ensure_lemonade_installed() + _check_version_compatibility() already handled all four states correctly. The new tests lock that in.

Resolves #774