refactor(structure): promote app to repo root + remove redundant workspace cruft

Standard production layout: the OKR app (was nested under AINative_OKR_CASAN5/) is now
the repository root. No more wrapper directory.

- Promote AINative_OKR_CASAN5/* -> repo root (backend/ frontend/ packages/ apps/
  .specify/ docs/ infra/ nginx/ scripts/ + configs). Merge tool dirs: .gitea (kept the
  active deploy ci.yml, added harness-ci.yml + runbooks), .claude (agents/commands +
  launch.json), .github moved up.
- Remove redundant: 00_SUBMISSION_PACKAGE, scattered root notes (FPT_CASAN_Full.md,
  tu-tuong-casan.md, casan-tu-sinh..., casan_harness_assessment.md, source-review...,
  README_CASAN5_REFINED.md), casan-next-plans/ and optimize-docs/ (competition/planning
  artifacts — roadmap + design history preserved in git log / commit messages).
- Update all references to the old layout:
  - .gitea/workflows/{ci,harness-ci}.yml, .github/workflows/{ci,deploy}.yml:
    working-directory .; drop AINative_OKR_CASAN5/ prefix; .specify/{tests,scripts}
    -> packages/casan-harness/... (.specify/logs state kept)
  - .claude/launch.json, .gitea/*-runbook.md: path prefixes
  - CLAUDE.md, README.md: docs/input -> apps/okr/domain/input
  - policy-bundle.yaml: 8 policy paths -> packages/casan-harness/...; manifest re-signed
- secrets-scan.sh: fixture excludes -> new package/domain paths.

Full gate from the new root: PASS=64 FAIL=0 SKIP=3.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/casan-harness/scripts/bash/verify-harness-reuse.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Verify CASAN Level 5 shared harness reuse across more than one project.
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/casan-paths.sh"
+PROJECT_ROOT="$CASAN_APP_ROOT"
+REGISTRY="$CASAN_HARNESS_ROOT/level5/project-registry.json"
+PACKAGE="$CASAN_HARNESS_ROOT/level5/harness-package.json"
+
+python - "$REGISTRY" "$PACKAGE" <<'PY'
+import json
+import sys
+registry = json.load(open(sys.argv[1], encoding="utf-8"))
+package = json.load(open(sys.argv[2], encoding="utf-8"))
+name = package["package"]
+version = package["version"]
+projects = [
+    p for p in registry["projects"]
+    if p.get("harness_package") == name and p.get("harness_version") == version
+]
+if len(projects) < 2:
+    raise SystemExit(f"HARNESS_REUSE_INSUFFICIENT package={name} version={version} count={len(projects)}")
+print(f"HARNESS_REUSE_VALID package={name} version={version} project_count={len(projects)}")
+PY