Initialize standalone Frame Dictation scaffold and install preflight

scripts/install-preflight.sh

@@ -0,0 +1,79 @@
+#!/bin/sh
+# Read-only host check for the proposed release installer. Does not install anything.
+set -u
+
+if [ "$#" -ne 0 ]; then
+    if [ "$#" -eq 1 ] && [ "$1" = --help ]; then
+        printf '%s\n' 'Usage: sh scripts/install-preflight.sh' \
+            'Checks the proposed Linux ARM64 installation prerequisites; makes no changes.'
+        exit 0
+    fi
+    printf '%s\n' 'No arguments are supported (except --help).' >&2
+    exit 2
+fi
+
+errors=0
+os=$(uname -s 2>/dev/null) || os=unknown
+arch=$(uname -m 2>/dev/null) || arch=unknown
+printf 'Host: %s %s\n' "$os" "$arch"
+if [ "$os" != Linux ] || [ "$arch" != aarch64 ]; then
+    printf '%s\n' 'Unsupported host: planned release payload is Linux AArch64 only.' >&2
+    errors=1
+fi
+
+libc=unknown
+if command -v getconf >/dev/null 2>&1; then
+    libc=$(getconf GNU_LIBC_VERSION 2>/dev/null) || libc=unknown
+fi
+printf 'C library: %s\n' "$libc"
+case "$libc" in
+    'glibc '*) ;;
+    *) printf '%s\n' 'Unsupported/unknown C library: planned ARM64 wheels require glibc.' >&2
+       errors=1 ;;
+esac
+
+# Expected for a future curl/tar release bootstrap, not for building from source.
+for dep in curl tar sha256sum mktemp mkdir mv; do
+    if command -v "$dep" >/dev/null 2>&1; then
+        printf 'Required tool: %s found\n' "$dep"
+    else
+        printf 'Required tool: %s MISSING\n' "$dep" >&2
+        errors=1
+    fi
+done
+
+if command -v git >/dev/null 2>&1; then
+    printf '%s\n' 'Git: found (not required for a release install)'
+else
+    printf '%s\n' 'Git: missing (not required for a release install)'
+fi
+if command -v uv >/dev/null 2>&1; then
+    printf '%s\n' 'uv: found (not required for a bundled runtime)'
+else
+    printf '%s\n' 'uv: missing (not required for a bundled runtime)'
+fi
+
+if command -v python3 >/dev/null 2>&1; then
+    version=$(python3 --version 2>&1) || version=unknown
+    printf 'System Python: %s (not required for a bundled runtime)\n' "$version"
+    case "$version" in
+        'Python 3.'*)
+            minor=${version#Python 3.}
+            minor=${minor%%.*}
+            case "$minor" in
+                ''|*[!0-9]*) printf '%s\n' 'System Python version could not be parsed.' ;;
+                *) if [ "$minor" -lt 12 ]; then
+                       printf '%s\n' 'System Python is older than 3.12; unsuitable for the proposed optional source worker.'
+                   fi ;;
+            esac ;;
+        *) printf '%s\n' 'System Python version could not be parsed.' ;;
+    esac
+else
+    printf '%s\n' 'System Python: missing (not required for a bundled runtime)'
+fi
+
+if [ "$errors" -ne 0 ]; then
+    printf '%s\n' 'Preflight failed. No changes were made.' >&2
+    exit 1
+fi
+printf '%s\n' 'Preflight passed for the proposed package format. No installer or release payload exists yet; nothing was installed.'