build: write all build output to build/ instead of the repo root

[Maxaubert]

Closes #484

Review item 2026-10-13 ("build.bat writes .obj files and every exe/pdb into the repo root"), owner decision: all build output moves to build\.

Layout

• build\: Wind.exe, WindTray.exe, WindConfig.exe, wind_tests.exe, their linker PDBs, and ui\dist mirrored by build.bat config (robocopy /MIR). This is the install layout, so ExeDir() lookups (WindTray.exe, WindConfig.exe, <exe dir>\ui\dist) work with no code change.
• build\obj\<target>\: objects, compiler PDBs and .res files per target (wind, wind_uiaccess, tray, config, test, check\core|tray|config). Nothing goes to src\ any more either (the old tray/config objects and .res files did).
• Working directory stays the repo root: build\wind_tests.exe still finds tests\fixtures, and WIND_SELFTEST=1 build\Wind.exe writes wind_selftest.png / wind_hdr_diag.txt to the cwd (root, still gitignored).
• Dev ini/logs: build\ is writable, so ResolveIniPath() / ResolveLogDir() keep a dev build's magnifier.ini, profiles\ and logs\ next to build\Wind.exe. Documented in 11 (including: deleting build\ deletes them, and an old root ini is no longer read).

Consumers changed

• build.bat: all targets (default, uiaccess via :core_exe, tray, config, test, check; installer unchanged apart from what wind.nsi packs)
• installer\wind.nsi: every File "..\X.exe" -> ..\build\X.exe, !if /FileExists "..\build\WindUA.exe", comment
• tools\release.ps1: $bin = $root\build; WindUA rename, missing-output check, signing
• tools\uiaccess_setup.ps1: deploy sources build\Wind.exe|WindConfig.exe|WindTray.exe (ui\dist still from the source copy)
• tools\installer_check.ps1: build\WindUA.exe probe for the local-signing checks
• .github/actions/build-installer/action.yml, .github/workflows/build.yml: comment/step name only (they consume dist\ only, unchanged)
• .gitignore: build/ first; root *.obj/*.exe/... and /magnifier.ini etc. kept with a comment (clones holding pre-build\ output, tools/testenv gamesim.exe)
• README.md Development, CLAUDE.md Commands + selftest gotcha, installer\README.md, docs\VERIFICATION.md
• docs/architecture: 11 (targets table, layout, dev runtime files, deploy, WindUA), 04 (selftest), 08 (dev ini), 12 (logs, selftest)
• Not changed (checked): tools\testenv\* and the probe scripts run C:\Program Files\Wind\Wind.exe only; ui/ has no root-path lookups; release.yml/alpha.yml only touch dist\.

Gates (local, this branch)

• build.bat check: exit 0
• build.bat test: 643/643 cases, exit 0
• build.bat uiaccess, build.bat tray, build.bat: exit 0 (only the pre-existing C4996 fopen warnings)
• npm ci + build.bat config: exit 0, build\WindConfig.exe and build\ui\dist\index.html present
• npm run test:rules: pass; npx playwright test: 205 passed
• build.bat installer with a hand-made build\WindUA.exe (uiaccess build renamed, as release.ps1 does): exit 0, every File source exists: ..\build\*.exe ok, LOCAL_SIGN path packed; silent install smoke skipped (non-elevated shell)
• git status --porcelain --ignored after all builds: nothing in the root besides the ignored build/, dist/ (installer), ui/dist, ui/node_modules
• tools\release.ps1 and tools\uiaccess_setup.ps1 not run (owner deploy); every path they use was Test-Path checked after the builds: all present

Not verified

• The elevated install/uninstall smoke in installer_check.ps1 and the CI release run (runner is admin)
• A live dev run of build\Wind.exe / build\WindConfig.exe (ini/logs landing in build\, settings page loading from build\ui\dist) and the signed deploy via uiaccess_setup.ps1

🤖 Generated with Claude Code

https://claude.ai/code/session_01TdjopXZfsUiesYxYLYHEdH