* Add German translation and harden paths against unset env vars
Add a German locale to the GUI, tray menu, usage alerts and website home page, and refuse to start when the home folder is unset or relative so nothing is written under the working folder; the pi plugin no longer adopts the user's PI_CODING_AGENT_DIR, and an inherited APPIMAGE no longer selects portable mode. Scripts refuse to run from the wrong folder or empty a shared out folder, and a new internal/testenv sandboxes every test package from the user's real files, which also fixes the Claude picker and Termux installer tests on Windows.
* Makefile: know magpie's folder by its go.mod, so paths with spaces work
The check compared $(CURDIR) with $(dir $(abspath …)), which make splits on spaces, so a checkout under 'My Projects' or 'John Doe' refused every target. It now reads go.mod relative to the working folder and wants magpie's module there: make -C and a symlinked Makefile work, make -f from another folder still stops before any recipe runs.
* i18n: German for the strings main added since, with a parity test
75 strings main added (group order, patterns, slow-start wait, usage caps, RTK savings …) get their German, and two that main dropped go. gui-de.test.cjs checks, as gui-ja does, that de has every zh string with its placeholders and tags, and that the window reads in German when picked or on a German system.
* appdir: ignore relative folder variables when reading, keep them for children
CheckEnv no longer unsets anything. magpie reads the XDG folders, APPDATA/LOCALAPPDATA and every agent's folder variable through appdir.Getenv/LookupEnv, which pass over a relative value; the environment stays as it is, so the agents magpie starts get the variable as the user set it. That covers what proc.UserPath lends from the login shell too, which is set after main's check and reached the desktop app unchecked. On Windows a path rooted on the current drive (\Users\x, Git Bash's /c/x) counts as usable, and magpie version and help answer without a home, before run makes any folder.
* Sandbox the tests main added since
internal/wslrun gets testenv's TestMain, and four tests main added that set HOME alone set their home with testenv.SetHome, so on Windows they don't read the runner's profile through USERPROFILE.
* agentenv: PI_CONFIG_DIR and OPENCODE_DB take relative names on purpose
omp puts $PI_CONFIG_DIR under the home and OpenCode a relative $OPENCODE_DB in its data folder, so neither depends on the working folder: appdir no longer passes them over.
* i18n: German for the Library's multi-select and System One's decision API
The 19 strings main added since (#791's skill multi-select, the decision API snippets) get their German; the one main replaced (four APIs → five APIs) goes.
* appdir: tidy the import into magpie's group; say what Go makes of /c/x
The appdir import joins the group of magpie's own imports where a file has one. rooted's comment now says that Go takes a Git Bash path like /c/x as \c\x on the current drive, not C:\x.
The rate is internal/fx: a free, no-key endpoint (open.er-api.com/v6/latest/USD), cached in memory and in a small file beside magpie's other caches (XDG_CACHE_HOME/magpie/fxrate.json) for 12h, refetched only once that's stale, and falling back to the last rate it ever had — or a fixed 7.2 — while offline; the currency row's tooltip names the rate and when it was learned. usage.FormatCost carries the $/¥ formatting (2 decimals above $1, 3 below, whole numbers above 100) that usage_cli.go and internal/tui/pages.go used to each have their own copy of; both now read Settings' currency once per command/redraw rather than per row. internal/gui/api.go exposes the rate on /api/settings always and on /api/state only when cny is actually chosen, so usd users' hot path never touches the network for a rate nothing shows with.
Tested with new internal/fx/fx_test.go (a fake server: fetches and caches, answers from memory then from the cache file with no further calls, refetches once stale, falls back to a stale cache or Fallback when offline, ignores a reply with no CNY rate), TestFXInState in internal/gui/fx_test.go, TestFmtCostShowsChosenCurrency in internal/tui/usage_test.go, and a new internal/gui/tests/currency.test.cjs in Chromium and WebKit, English and Chinese (the Usage page's $ by default and ¥12.34×7.2 once cny is picked, the currency row's labels/state/tooltip, a real wheel scroll deep into Settings left alone by picking a currency, the choice surviving a reload). go build -tags nogui, GOOS=linux and GOOS=windows builds, and go test -tags nogui -count=1 ./... all pass clean.
A fetch that failed is not tried again for 10 minutes (the stale or fixed rate shown at once meanwhile), so offline each state() does not wait up to 4s on the network: TestGetDoesNotRetryAFailedFetchAtOnce.
tobitege