fix: comprehensive quality improvements

- Fix 2 backend test failures (projectFolders validation, StressTest timeout)
- Fix frontend test dependency (@testing-library/dom)
- Delete App.tsx.bak from repo
- Add rate limiting on auth endpoints (login: 10/min, register: 3/min)
- Add .env.example with all environment variables
- Update BAUPLAN.md with accurate phase status (16/21 phases implemented)
- Add OpenAPI/Swagger documentation (docs/openapi.yaml)
- Add E2E workflow test (15 steps: register→project→drawing→layer→element→CRUD→delete)
- Add Forgejo CI/CD pipeline (.forgejo/workflows/ci.yml)
- Improve .gitignore (db-wal, .env.*, *.bak, coverage)
- Add security comment for default user in schema.sql

All 628 tests passing (254 backend + 374 frontend)

backend/package-lock.json

@@ -1154,49 +1154,6 @@
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-        "module-error": "^1.0.1"
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-      "funding": [
-        {
-          "type": "github",
-          "url": "https://github.com/sponsors/feross"
-        },
-        {
-          "type": "patreon",
-          "url": "https://www.patreon.com/feross"
-        },
-        {
-          "type": "consulting",
-          "url": "https://feross.org/support"
-        }
-      ],
-      "optional": true,
-      "peer": true,
-      "dependencies": {
-        "base64-js": "^1.3.1",
-        "ieee754": "^1.2.1"
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     "node_modules/abstract-logging": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/abstract-logging/-/abstract-logging-2.0.1.tgz",
@@ -2075,16 +2032,6 @@
         "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
       }
     },
-    "node_modules/level-supports": {
-      "version": "6.2.0",
-      "resolved": "https://registry.npmjs.org/level-supports/-/level-supports-6.2.0.tgz",
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-      "optional": true,
-      "peer": true,
-      "engines": {
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     "node_modules/level-transcoder": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/level-transcoder/-/level-transcoder-1.0.1.tgz",
@@ -2489,16 +2436,6 @@
         "@jridgewell/sourcemap-codec": "^1.5.5"
       }
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-    "node_modules/maybe-combine-errors": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/maybe-combine-errors/-/maybe-combine-errors-1.0.0.tgz",
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-      "optional": true,
-      "peer": true,
-      "engines": {
-        "node": ">=10"
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     "node_modules/mime": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/mime/-/mime-3.0.0.tgz",