feat(config): wire launcher scripts and compose to config.json (#2)

- common.sh: load_config() exports MOSAIC_DATA_ROOT/PROVIDER/MODEL; fails closed
- compose.yaml: dataRoot mount and provider/model are required env (:? errors)
- build/hello/verify load config before any mutation; no silent bootstrap
- reset.sh: target resolved from configured dataRoot; all safety checks kept

Verified: compose fails without launcher env; verify/reset fail on missing
config; config-driven hello+verify pass; symlink refusal with sandboxed
config (canary survived); config checksum unchanged across reset+rerun.

Closes #2

scripts/build.sh

@@ -5,6 +5,8 @@ cd "$(dirname "$0")/.."
 # shellcheck source=common.sh
 source scripts/common.sh
 
+load_config
+
 bootstrap_runtime_dir
 
 docker compose build

scripts/common.sh

@@ -1,11 +1,27 @@
-# Shared helpers for the POC host scripts. Not a documented entry point.
+# Shared helpers for the Mosaic host scripts. Not a documented entry point.
 
-MOSAIC_DEV_DIR="/home/jwoltje/.mosaic-dev"
 POC_ROOT_MARKER=".mosaic-poc-root"
 
-# Ensure the runtime state directory exists and carries this project's
-# ownership marker. The marker is what scripts/reset.sh requires before
-# it will delete anything.
+# Load and validate the Mosaic configuration (config.json), exporting
+# MOSAIC_DATA_ROOT, MOSAIC_PROVIDER, and MOSAIC_MODEL.
+#
+# Fails closed: a missing or invalid configuration aborts the calling
+# script before any container or filesystem mutation. Run paths never
+# auto-bootstrap; use scripts/bootstrap.sh explicitly.
+load_config() {
+    local config_env
+    if ! config_env="$(node scripts/mosaic-config.mjs env)"; then
+        echo "common: configuration load failed" >&2
+        exit 1
+    fi
+    eval "$config_env"
+    export MOSAIC_DATA_ROOT MOSAIC_PROVIDER MOSAIC_MODEL
+    MOSAIC_DEV_DIR="$MOSAIC_DATA_ROOT"
+}
+
+# Ensure the configured runtime data directory exists and carries this
+# project's ownership marker. The marker is what scripts/reset.sh requires
+# before it will delete anything.
 bootstrap_runtime_dir() {
     if [ ! -d "$MOSAIC_DEV_DIR" ]; then
         mkdir -p "$MOSAIC_DEV_DIR"

scripts/hello.sh

@@ -10,6 +10,8 @@ cd "$(dirname "$0")/.."
 # shellcheck source=common.sh
 source scripts/common.sh
 
+load_config
+
 bootstrap_runtime_dir
 
 # -T: no pseudo-TTY, so stdout is clean model output.

scripts/reset.sh

@@ -7,9 +7,15 @@
 #      created by this project.
 # Any failed check aborts with nothing deleted.
 set -euo pipefail
+cd "$(dirname "$0")/.."
+# shellcheck source=common.sh
+source scripts/common.sh
 
-TARGET="/home/jwoltje/.mosaic-dev"
-MARKER=".mosaic-poc-root"
+# Reset operates on the CONFIGURED data root. Configuration itself is
+# never a reset target; a missing/invalid configuration aborts here.
+load_config
+TARGET="$MOSAIC_DATA_ROOT"
+MARKER="$POC_ROOT_MARKER"
 
 fail() {
     echo "reset: refusing to delete: $*" >&2

scripts/test-config.sh

@@ -0,0 +1,142 @@
+#!/usr/bin/env bash
+# Fast, sandboxed selftests for the configuration layer.
+#
+# No Docker, no network, no credentials: every case runs against a
+# temporary config via MOSAIC_CONFIG. Suitable for frequent local runs.
+set -uo pipefail
+cd "$(dirname "$0")/.."
+
+SANDBOX="$(mktemp -d)"
+trap 'rm -rf "$SANDBOX"' EXIT
+
+PASS=0
+FAIL=0
+
+# expect_exit NAME EXPECTED_RC -- command...
+expect_exit() {
+    local name="$1" expected="$2"
+    shift 3 # name, expected, "--"
+    local rc
+    "$@" >/dev/null 2>&1
+    rc=$?
+    if [ "$rc" -eq "$expected" ]; then
+        PASS=$((PASS + 1))
+        echo "ok   $name (exit $rc)"
+    else
+        FAIL=$((FAIL + 1))
+        echo "FAIL $name (exit $rc, expected $expected)"
+    fi
+}
+
+CONFIG_OP="node scripts/mosaic-config.mjs"
+
+valid_body() {
+    cat <<EOF
+{"configVersion":1,"environment":"development","dataRoot":"$1","execution":{"backend":"docker","provider":"zai","model":"glm-5.3-flash"}}
+EOF
+}
+
+cfg() { printf '%s' "$2" > "$SANDBOX/$1"; }
+
+DATA_ROOT="$SANDBOX/data"
+
+# --- bootstrap ---
+rm -f "$SANDBOX/config.json"
+expect_exit "bootstrap creates default when absent" 0 -- \
+    env MOSAIC_CONFIG="$SANDBOX/config.json" $CONFIG_OP bootstrap
+[ -f "$SANDBOX/config.json" ] && { PASS=$((PASS+1)); echo "ok   bootstrap wrote config file"; } \
+    || { FAIL=$((FAIL+1)); echo "FAIL bootstrap wrote config file"; }
+
+SUM_BEFORE=$(sha256sum "$SANDBOX/config.json" | cut -d' ' -f1)
+MTIME_BEFORE=$(stat -c %Y "$SANDBOX/config.json")
+sleep 1.1
+expect_exit "bootstrap is idempotent on existing config" 0 -- \
+    env MOSAIC_CONFIG="$SANDBOX/config.json" $CONFIG_OP bootstrap
+SUM_AFTER=$(sha256sum "$SANDBOX/config.json" | cut -d' ' -f1)
+MTIME_AFTER=$(stat -c %Y "$SANDBOX/config.json")
+if [ "$SUM_BEFORE" = "$SUM_AFTER" ] && [ "$MTIME_BEFORE" = "$MTIME_AFTER" ]; then
+    PASS=$((PASS+1)); echo "ok   bootstrap did not rewrite existing config"
+else
+    FAIL=$((FAIL+1)); echo "FAIL bootstrap rewrote existing config"
+fi
+
+# --- validate ---
+expect_exit "validate missing config exits 3" 3 -- \
+    env MOSAIC_CONFIG="$SANDBOX/absent.json" $CONFIG_OP validate
+
+cfg invalid.json '{'
+expect_exit "malformed JSON exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/invalid.json" $CONFIG_OP validate
+
+cfg badversion.json '{"configVersion":2,"environment":"development","dataRoot":"'$DATA_ROOT'","execution":{"backend":"docker","provider":"zai","model":"m"}}'
+expect_exit "unsupported configVersion exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/badversion.json" $CONFIG_OP validate
+
+cfg unknownkey.json '{"configVersion":1,"environment":"development","dataRoot":"'$DATA_ROOT'","extra":true,"execution":{"backend":"docker","provider":"zai","model":"m"}}'
+expect_exit "unknown top-level key exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/unknownkey.json" $CONFIG_OP validate
+
+cfg unknownexec.json '{"configVersion":1,"environment":"development","dataRoot":"'$DATA_ROOT'","execution":{"backend":"docker","provider":"zai","model":"m","extra":1}}'
+expect_exit "unknown execution key exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/unknownexec.json" $CONFIG_OP validate
+
+cfg badbackend.json '{"configVersion":1,"environment":"development","dataRoot":"'$DATA_ROOT'","execution":{"backend":"podman","provider":"zai","model":"m"}}'
+expect_exit "unsupported backend exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/badbackend.json" $CONFIG_OP validate
+
+cfg badenv.json '{"configVersion":1,"environment":"staging","dataRoot":"'$DATA_ROOT'","execution":{"backend":"docker","provider":"zai","model":"m"}}'
+expect_exit "unsupported environment exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/badenv.json" $CONFIG_OP validate
+
+cfg relative.json '{"configVersion":1,"environment":"development","dataRoot":"relative/path","execution":{"backend":"docker","provider":"zai","model":"m"}}'
+expect_exit "relative dataRoot exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/relative.json" $CONFIG_OP validate
+
+cfg traversal.json '{"configVersion":1,"environment":"development","dataRoot":"/tmp/../home/x","execution":{"backend":"docker","provider":"zai","model":"m"}}'
+expect_exit "non-canonical dataRoot exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/traversal.json" $CONFIG_OP validate
+
+cfg root.json '{"configVersion":1,"environment":"development","dataRoot":"/","execution":{"backend":"docker","provider":"zai","model":"m"}}'
+expect_exit "filesystem root dataRoot exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/root.json" $CONFIG_OP validate
+
+cfg home.json '{"configVersion":1,"environment":"development","dataRoot":"'$HOME'","execution":{"backend":"docker","provider":"zai","model":"m"}}'
+expect_exit "home directory dataRoot exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/home.json" $CONFIG_OP validate
+
+cfg cfgdir.json '{"configVersion":1,"environment":"development","dataRoot":"'$SANDBOX'","execution":{"backend":"docker","provider":"zai","model":"m"}}'
+expect_exit "dataRoot containing config dir exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/cfgdir.json" $CONFIG_OP validate
+
+cfg ctrlchar.json '{"configVersion":1,"environment":"development","dataRoot":"'$DATA_ROOT'","execution":{"backend":"docker","provider":"z\nai","model":"m"}}'
+expect_exit "control character in provider exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/ctrlchar.json" $CONFIG_OP validate
+
+cfg symlink.json
+ln -sf "$SANDBOX/invalid.json" "$SANDBOX/symlink.json" 2>/dev/null
+expect_exit "symlinked config file exits 2" 2 -- \
+    env MOSAIC_CONFIG="$SANDBOX/symlink.json" $CONFIG_OP validate
+
+# --- env resolution ---
+cfg valid.json "$(valid_body "$DATA_ROOT")"
+EVAL_OUT="$(MOSAIC_CONFIG="$SANDBOX/valid.json" $CONFIG_OP env)" || true
+if eval "$EVAL_OUT" 2>/dev/null && [ "$MOSAIC_DATA_ROOT" = "$DATA_ROOT" ] \
+    && [ "$MOSAIC_PROVIDER" = "zai" ] && [ "$MOSAIC_MODEL" = "glm-5.3-flash" ]; then
+    PASS=$((PASS+1)); echo "ok   env exports resolve correctly"
+else
+    FAIL=$((FAIL+1)); echo "FAIL env exports resolve correctly"
+fi
+
+# --- validation must not modify the file ---
+SUM_INVALID_BEFORE=$(sha256sum "$SANDBOX/invalid.json" | cut -d' ' -f1)
+MOSAIC_CONFIG="$SANDBOX/invalid.json" $CONFIG_OP validate >/dev/null 2>&1
+SUM_INVALID_AFTER=$(sha256sum "$SANDBOX/invalid.json" | cut -d' ' -f1)
+if [ "$SUM_INVALID_BEFORE" = "$SUM_INVALID_AFTER" ]; then
+    PASS=$((PASS+1)); echo "ok   failed validation modified nothing"
+else
+    FAIL=$((FAIL+1)); echo "FAIL failed validation modified the file"
+fi
+
+echo
+echo "selftest: $PASS passed, $FAIL failed"
+[ "$FAIL" -eq 0 ]

scripts/verify.sh

@@ -17,6 +17,8 @@ source scripts/common.sh
 IMAGE="mosaic-poc-agent:0.84.4"
 EXPECTED="${EXPECTED_MARKER:-MOSAIC_HELLO_OK}"
 
+load_config
+
 # 1. Build the image only if it is not already present.
 if ! docker image inspect "$IMAGE" >/dev/null 2>&1; then
     echo "verify: image $IMAGE not found, building..." >&2