FHS F0: introduce ARCHR_* path vocabulary

profile.d/010-archr-fhs exports seven variables (ARCHR_ETC,
ARCHR_CONFIG, ARCHR_CACHE, ARCHR_DATA, ARCHR_GAMES, ARCHR_LOG,
ARCHR_TMP) that future ArchR scripts should read instead of
hardcoding /storage/.config and siblings. Every variable defaults to
its current /storage location so behaviour is identical to today;
subsequent FHS phases will flip the right-hand side without touching
the callers.

archr(7) gains an ENVIRONMENT section describing each variable, its
current value and its FHS target so anyone writing a new script knows
which name to use.

docs/fhs-mapping.md: F0 marked complete; F1..F7 still pending.

Risk: zero. The new file is read at login but only sets variables.
No script reads them yet.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/fhs-mapping.md

@@ -172,6 +172,6 @@ Migration scripts ficam em `projects/ArchR/packages/archr/sources/post-update.d/
 
 - [x] Auditoria de 297 paths concluída (2026-06-23).
 - [x] Mapeamento por classe definido.
-- [ ] Fase 0 (vocabulário) — em andamento.
+- [x] Fase 0 concluída (2026-06-23): `010-archr-fhs` em `/etc/profile.d`, archr(7) com seção ENVIRONMENT, vars apontando para `/storage/...`. Risco zero.
 - [ ] Fase 1 — não iniciada.
 - [ ] Fase 2..7 — não iniciadas.

projects/ArchR/packages/archr/profile.d/010-archr-fhs

@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2026-present ArchR (https://github.com/archr-linux)
+#
+# ArchR Filesystem Hierarchy vocabulary
+# -------------------------------------
+# Phase 0 of the FHS migration (Arch-ification 2.2).
+#
+# These variables establish the Arch-friendly vocabulary for paths that
+# ArchR scripts use. During this phase they point to the legacy
+# LibreELEC-style /storage layout, so nothing changes at runtime.
+# Subsequent phases migrate each path class to its FHS destination by
+# flipping the right-hand side of the assignments here, while the
+# variable name stays stable for callers.
+#
+# See docs/fhs-mapping.md in the source tree for the full plan.
+#
+# Convention for downstream scripts: always read paths via these
+# variables, never hardcode "/storage/.config" again. Example:
+#
+#   config_dir="${ARCHR_CONFIG}/drastic"
+#   instead of
+#   config_dir="/storage/.config/drastic"
+#
+# When a script is migrated to use ${ARCHR_X}, the next phase can move
+# the underlying data without touching that script.
+
+# Class A: system configuration (-> /etc/archr eventually)
+export ARCHR_ETC="${ARCHR_ETC:-/storage/.config}"
+
+# Class B: user/app configuration (-> /var/lib/archr/config eventually)
+export ARCHR_CONFIG="${ARCHR_CONFIG:-/storage/.config}"
+
+# Class C: regenerable cache (-> /var/cache/archr eventually)
+export ARCHR_CACHE="${ARCHR_CACHE:-/storage/.cache}"
+
+# Class D: persistent state/data (-> /var/lib/archr/data eventually)
+export ARCHR_DATA="${ARCHR_DATA:-/storage/.local/share}"
+
+# Class E: user games library and adjacent media (-> /var/lib/archr/games eventually)
+export ARCHR_GAMES="${ARCHR_GAMES:-/storage/roms}"
+
+# Class F: log files (-> /var/log/archr eventually)
+export ARCHR_LOG="${ARCHR_LOG:-/storage/.cache/log}"
+
+# Class G: ephemeral temp (-> /var/tmp/archr eventually)
+export ARCHR_TMP="${ARCHR_TMP:-/storage/.tmp}"

projects/ArchR/packages/archr/sources/man/archr.7

@@ -62,6 +62,60 @@ Send anonymized telemetry when the user opts in.
 .TP
 .B archr-retroachievements-info
 Display RetroAchievements account state and recent unlocks.
+.SH ENVIRONMENT
+ArchR scripts read filesystem paths through the
+.B ARCHR_*
+family of variables, exported by
+.IR /etc/profile.d/010-archr-fhs .
+This vocabulary is stable; the underlying paths migrate to FHS locations
+across releases (see
+.IR docs/fhs-mapping.md
+in the source tree). Callers should never hardcode
+.IR /storage/.config
+or its siblings; use the variable instead.
+.TP
+.B ARCHR_ETC
+System configuration. Currently
+.IR /storage/.config ;
+target
+.IR /etc/archr .
+.TP
+.B ARCHR_CONFIG
+User and application configuration (emulators, EmulationStation,
+PortMaster). Currently
+.IR /storage/.config ;
+target
+.IR /var/lib/archr/config .
+.TP
+.B ARCHR_CACHE
+Regenerable cache (shader cache, fontconfig, service state). Currently
+.IR /storage/.cache ;
+target
+.IR /var/cache/archr .
+.TP
+.B ARCHR_DATA
+Persistent state and data. Currently
+.IR /storage/.local/share ;
+target
+.IR /var/lib/archr/data .
+.TP
+.B ARCHR_GAMES
+Games library root (ROMs, saves, screenshots, recordings). Currently
+.IR /storage/roms ;
+target
+.IR /var/lib/archr/games .
+.TP
+.B ARCHR_LOG
+Log files. Currently
+.IR /storage/.cache/log ;
+target
+.IR /var/log/archr .
+.TP
+.B ARCHR_TMP
+Ephemeral temp. Currently
+.IR /storage/.tmp ;
+target
+.IR /var/tmp/archr .
 .SH FILES
 .TP
 .I /etc/os-release