fix: address independent review - provision the vhost, fix host-vs-container reporting

Addresses the two valid items from the independent review (code/security/infra all
Approved; these were Minor/Needs-Change items).

1. provision.sh left the nginx vhost as a manual "see README" step, which broke the
   project's own repeatability requirement (FR-9): a rebuild from scratch would have
   served the distro default page instead of Atheos. The vhost is now written by the
   script itself, the distro default.conf is removed, and the script ASSERTS the socket
   contract (nginx fastcgi_pass == php-fpm pool listen) before Atheos is installed - so
   a 502 can only ever mean an nginx/php-fpm problem, never be mistaken for an Atheos one.

2. `free` and `uptime` reported the PVE HOST inside the container (a container that had
   restarted seconds earlier claimed "up 2 days"), which is misleading in monitoring and
   in the test output.

   The review suggested `apk add lxcfs` in the guest. That is NOT the fix - lxcfs is a
   host-provided FUSE filesystem, not a guest package, and measurement showed it is
   already working correctly here:
     /proc/meminfo -> MemTotal: 1048576 kB   (our 1024 MB limit)
     /proc/uptime  -> container seconds
     /proc/cpuinfo -> 2 processors

   The real cause: on Alpine, `free`/`uptime` are BUSYBOX applets that read via the
   sysinfo() SYSCALL, which lxcfs cannot intercept. procps-ng ships binaries that read
   the lxcfs-virtualised /proc files instead. Measured on the guest:
     procps-ng free   -> 1024 MB     (correct)
     busybox   free   -> 15701 MB    (host)
     procps-ng uptime -> up 2 min    (correct)
     busybox   uptime -> up 2 days   (host)

   So provision.sh now installs procps-ng, and build-and-test.sh reports container-
   accurate figures (detecting it via apk rather than a binary-existence probe, since
   the busybox applets are plain files too).

Verified after the change: build-and-test 40 passed / 0 failed; socket contract MATCH;
resource line now reads "18MB used of 1024MB, up 2 min".

scripts/provision.sh

@@ -95,7 +95,10 @@ pct exec "$VMID" -- sh -c '
   apk add --no-cache nginx php83 php83-fpm \
     php83-session php83-zip php83-openssl php83-mbstring php83-ctype php83-curl \
     php83-dom php83-json php83-iconv php83-fileinfo php83-simplexml php83-xml \
-    php83-tokenizer >/dev/null 2>&1
+    php83-tokenizer procps-ng >/dev/null 2>&1
+  # procps-ng (NOT lxcfs) is what makes free/uptime report the CONTAINER rather than the host.
+  # busybox applets use the sysinfo() syscall, which lxcfs cannot intercept; procps-ng reads the
+  # lxcfs-virtualised /proc/meminfo and /proc/uptime. Verified: procps free -> 1024MB, busybox -> host.
   # dedicated service user (I-4: FPM user == file owner == key owner)
   adduser -D -s /sbin/nologin -h /home/atheos atheos 2>/dev/null || true
   mkdir -p /var/www/atheos/workspace /run/php-fpm83 /var/log/nginx
@@ -114,11 +117,60 @@ pct exec "$VMID" -- sh -c '
   grep -q "^listen.mode"  /etc/php83/php-fpm.d/www.conf || echo "listen.mode = 0660"  >> /etc/php83/php-fpm.d/www.conf
   rc-update add nginx default >/dev/null 2>&1
   rc-update add php-fpm83 default >/dev/null 2>&1
+'
+
+# --- nginx vhost: installed BY THE SCRIPT so provisioning is repeatable end-to-end -----------
+# (review finding: leaving this as a manual "see README" step broke the project's own
+#  repeatability requirement FR-9 — a rebuild from scratch would serve the distro default page)
+pct exec "$VMID" -- sh -c "cat > /etc/nginx/http.d/atheos.conf" <<'NGINXCONF'
+server {
+    listen 80 default_server;
+    listen [::]:80 default_server;
+    server_name _;
+    root /var/www/atheos;
+    index index.php index.html;
+    access_log /var/log/nginx/atheos.access.log;
+    error_log  /var/log/nginx/atheos.error.log;
+
+    # The socket path here MUST byte-match the pool's `listen =` in
+    # /etc/php83/php-fpm.d/www.conf (interface I-1 - a mismatch yields a bare 502).
+    location ~ \.php$ {
+        try_files $uri =404;
+        fastcgi_split_path_info ^(.+\.php)(/.+)$;
+        fastcgi_pass unix:/run/php-fpm83/php-fpm.sock;
+        fastcgi_index index.php;
+        include fastcgi.conf;
+        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
+    }
+    location / { try_files $uri $uri/ =404; }
+
+    # never serve the VCS dir, the app's private data, or dotfiles
+    location ~ /\.git  { deny all; }
+    location ~ /\.ssh  { deny all; }
+    location ~ /\.      { deny all; }
+    location ~ ^/data/ { deny all; }
+    location ~ ^/(config\.php|common\.php|controller\.php|traits/) { deny all; }
+    location ~* \.(md|py|sh|log|conf|ini|sql|bak|orig)$ { deny all; }
+
+    add_header X-Content-Type-Options "nosniff" always;
+    add_header X-Frame-Options "SAMEORIGIN" always;
+    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
+
+    client_max_body_size 64m;
+}
+NGINXCONF
+# remove the distro default vhost so ours is authoritative, then start the stack
+pct exec "$VMID" -- sh -c '
+  rm -f /etc/nginx/http.d/default.conf
   rc-service php-fpm83 restart >/dev/null 2>&1
   rc-service nginx restart >/dev/null 2>&1
+  sleep 2
+  # prove the socket contract holds BEFORE Atheos is installed, so a 502 can only ever
+  # mean an nginx/php-fpm problem and never be confused with an Atheos problem
+  SOCK=$(sed -n "s/^listen = //p" /etc/php83/php-fpm.d/www.conf | head -1)
+  NGX=$(sed -n "s/.*fastcgi_pass unix:\([^;]*\);.*/\1/p" /etc/nginx/http.d/atheos.conf | head -1)
+  if [ "$SOCK" = "$NGX" ]; then echo "socket contract OK: $SOCK"; else echo "SOCKET MISMATCH: pool=$SOCK nginx=$NGX"; exit 1; fi
 '
-echo "NOTE: install the nginx vhost from files/atheos.conf (see README) into /etc/nginx/http.d/atheos.conf"
-echo "      and remove /etc/nginx/http.d/default.conf, then: rc-service nginx restart"
 
 # ==============================================================================
 log "6/9 Atheos install at the pinned commit (U3)"