# Pocket Engineer 0.5.0-rc2 — anonymous Render downloads

This corrective preview delivers installers publicly from [Pocket Engineer on Render](https://pocket-engineer.onrender.com/), independently of GitHub repository visibility. No GitHub account is needed for the Render download files. Build validation and post-publication anonymous access checks are recorded separately.

Post-publication results: all five actual browser downloads matched their checksums; downloaded packages passed Windows/macOS/Ubuntu/NixOS execution, four Android emulator tests and 82 website tests. The live site's offline restart and cached-app update also passed. See [public validation](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/PUBLIC_DOWNLOAD_VALIDATION.json). These text-only metadata updates leave installer/archive bytes unchanged.

## Download and run

- [Android preview APK](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/PocketEngineer-0.5.0-android-preview.apk): Android 7+ with an updated System WebView; native C++ and all demos bundled, no INTERNET permission. Optimized but development-signed. Export history before replacing a differently signed preview.
- [Windows x64 ZIP](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/PocketEngineer-0.5.0-Windows-x64.zip): extract all files; open `Start-Pocket-Engineer.cmd`.
- [macOS universal ZIP](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/PocketEngineer-0.5.0-macOS-universal.zip): macOS 11+; extract, then open `Start-Pocket-Engineer.command`. Not notarized. CI executes Apple Silicon, not an Intel Mac.
- [Linux x64 ZIP](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/PocketEngineer-0.5.0-Linux-x64.zip): extract, then run `sh Start-Pocket-Engineer.sh`. Static C/C++ runtime for Ubuntu and NixOS compatibility.
- [Offline website ZIP](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/PocketEngineer-0.5.0-offline-website.zip): complete WASM site for localhost or HTTPS hosting, not double-clicked `file://` use. Desktop ZIPs provide the local launcher without needing Python or Node.

Keep the desktop launcher's terminal open. Executables are not code-signed; do not disable system-wide security protections. [SHA-256 checksums](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/SHA256SUMS.txt) and [build provenance](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/BUILD_SOURCE.txt) identify exact files.

## What changed

An earlier anonymous GitHub asset request returned 404 while the repository was reported private; authenticated CI downloads did not establish public availability. This release moves public delivery to a checksum-verified, versioned directory on the existing Render site. The implementation did not change repository visibility or signing credentials. A later read-only check on September 12 at approximately 15:31 UTC reports the repository public; Render downloads do not depend on that setting.

Installers are excluded from service-worker caches, Android assets, desktop packages and the website ZIP, preventing recursive package growth. Download navigation bypasses the service worker so it cannot substitute the app's HTML for an APK, ZIP or checksum file. The desktop download workflow now uses unauthenticated requests to Render.

The 0.5 visual labs remain: clickable 2–6 variable K-maps, matrix forms, DC/AC/transient circuit drawing and analysis, state-machine diagrams, and thirteen signals/transform operations. Original demos contain 55 topics × three difficulties × 5,000 stored cases. Choose a category and difficulty, calibrate, run a page or all 5,000, cancel and export expected/actual values. RK4 filenames now load correctly.

Visit the site while connected and wait for **Ready offline**; then the same Render URL works in the same browser after a full offline restart. The complete cached app and demo bank are about 9.2 MB. New private profiles, first-ever offline visits, cleared storage and cache eviction cannot preserve an installation that is absent.

## Evidence and limits

Build source: `81feb663ea870a998de948cfc368f1aaf564361a`. [Package CI 34700452345](https://github.com/MuhammadTahaBinZaeem/FOP-Project/actions/runs/34700452345) passes Windows, macOS, Linux and both Android build-type instrumentation runs; sentinel-file tests verify that installers are excluded from packages. [Website CI 34700453933](https://github.com/MuhammadTahaBinZaeem/FOP-Project/actions/runs/34700453933) and local browser validation pass **82/82 tests**. The complete offline UI replay passes **825,000/825,000 stored comparisons**, with every exported record audited against the hashed bank bytes.

The unchanged numerical engine's independent/edge tests pass 1,606,929 checks; natural-input tests pass 4,112; workbench tests pass 23,374; additional engineering studies pass 31,941. All five native suites and their ASan/UBSan runs pass. These are distinct coverage categories, not an inflated count of independently proven answers. C++ is **82.116%** of maintained runtime code, or **77.095% including HTML/CSS**.

[Per-case demo comparisons](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/PocketEngineer-0.5.0-demo-comparisons.tar.gz) and [test evidence](https://pocket-engineer.onrender.com/downloads/v0.5.0-rc2/PocketEngineer-0.5.0-test-evidence.zip) are separate optional downloads, not part of the offline app cache. Snapshot equality is regression evidence, not independent mathematical proof. New engineering labs have independent tests and presets, not an invented 5,000-case bank for each new operation.

Supported families and work limits are explicit; this is not unrestricted SPICE, symbolic ODE solving or universal natural-language interpretation. C++ remains above 77% of maintained runtime source including HTML/CSS; tests, documentation, archives and generated glue are excluded consistently.

Physical-phone smoothness, production Android signing, desktop signing/notarization and 16 KB Android runtime-device testing remain unverified. Emulator traces include stalls; no universal zero-lag or 60 FPS claim is made. GitHub artifact access may require authentication; the Render files above are separately tested without it.