M0: toolchain, monorepo scaffold, gateway plugin skeleton, CMP app

- gateway-plugin/: android platform plugin (plugin.yaml + adapter.py
  register(ctx) + no-op AndroidAdapter) + stub modules for M1-M5
- app/: Compose Multiplatform project (shared KMP + androidApp +
  desktopApp) with Gradle wrapper; builds :androidApp:assembleDebug
  and :desktopApp:compileKotlin
- scripts/guard_hermes_agent.sh + pre-commit hook: fail if hermes-agent/
  is staged (read-only reference, never committed)
- .gitignore excludes hermes-agent/; docs/ reference library

scripts/guard_hermes_agent.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+# Guard: hermes-agent/ is a read-only research reference and must NEVER be
+# committed, pushed, or shipped. This fails the commit/CI if any path under
+# hermes-agent/ is staged.
+#
+# Usage:
+#   - pre-commit hook:  scripts/guard_hermes_agent.sh --staged
+#   - CI / manual:      scripts/guard_hermes_agent.sh --staged
+#
+# Exit 0 = clean, exit 1 = hermes-agent/ paths detected.
+
+set -euo pipefail
+
+MODE="${1:---staged}"
+
+if [[ "$MODE" == "--staged" ]]; then
+    # Every path currently in the index. Using `git ls-files --cached` (rather
+    # than `git diff --cached`) makes this robust on the very first commit,
+    # where no HEAD exists yet and `git diff --cached` is unreliable. We never
+    # want hermes-agent/ in the index at all, so blocking on its presence is
+    # both correct and safe.
+    mapfile -t BAD < <(git ls-files --cached | grep -E '^hermes-agent/' || true)
+else
+    # Fallback: any tracked file under hermes-agent/.
+    mapfile -t BAD < <(git ls-files | grep -E '^hermes-agent/' || true)
+fi
+
+if [[ ${#BAD[@]} -gt 0 ]]; then
+    echo "ERROR: the following hermes-agent/ paths are staged. This directory is a" >&2
+    echo "read-only research reference and must NEVER be committed (see .gitignore" >&2
+    echo "and docs/00-overview.md 'Disclaimers'). Unstage them with:" >&2
+    echo "    git restore --staged <path>" >&2
+    printf '  %s\n' "${BAD[@]}" >&2
+    exit 1
+fi
+
+exit 0