chore: remove dead code from previous #815 fix attempts

PR #840 fixed issue #815 in the Electron main process via
will-prevent-unload + preventDefault. The renderer-side workarounds
introduced by previous fix attempts (#642, #648) are no longer needed
and never had effect for their stated purpose.

Removed:
- configuration={ confirmExit: false } in DrawIoEmbed
  confirmExit is not a recognized draw.io config key (zero matches in
  jgraph/drawio source). This was always dead code.

- modified=0 / keepmodified=0 URL parameters
  Per drawio source (app.min.js:14898), these only suppress the
  post-save modified-flag clearing — they do not prevent edits from
  setting editor.modified=true. They were ineffective for blocking
  beforeunload prompts and actually prevented draw.io from clearing
  its modified flag after save.

- canPersist / canPersistChecked state and isIndexedDBUsable() probe
  Their only purpose was gating the dead config above. Removing them
  also removes a startup delay before the iframe renders.

- handleDrawioAutoSave wrapper
  After PR #780 stripped its body, it was a pure passthrough useCallback.
  Now passes handleDiagramAutoSave directly to onAutoSave.

- withDB / isClosingError / resetDBPromise / onversionchange / onclose
  / terminated handlers in lib/session-storage.ts and lib/template-storage.ts
  PR #648 added these to recover from 'IDBDatabase: connection is closing'
  errors that PR #642's first land caused via db.close() on the shared
  singleton. That bug was already fixed in c5de1a1 (re-land of #642),
  three minutes before PR #648 commits started. The retry handlers
  defend against multi-tab / version-change scenarios that cannot occur
  in this single-instance Electron app (requestSingleInstanceLock).
  template-storage.ts copied the same pattern when introduced by #773.

Verified:
- npx tsc --noEmit passes
- Manual test in dev mode: session save/load works, template create works,
  diagram-only persistence works.

package.json

@@ -1,6 +1,6 @@
 {
     "name": "next-ai-draw-io",
-    "version": "0.4.16",
+    "version": "0.4.15",
     "license": "Apache-2.0",
     "private": true,
     "main": "dist-electron/main/index.js",
@@ -49,9 +49,9 @@
         "@langfuse/tracing": "^4.4.9",
         "@next/third-parties": "^16.0.6",
         "@opennextjs/cloudflare": "^1.17.1",
-        "@openrouter/ai-sdk-provider": "^2.0.0",
+        "@openrouter/ai-sdk-provider": "^1.5.4",
         "@opentelemetry/api": "^1.9.0",
-        "@opentelemetry/exporter-trace-otlp-http": "^0.216.0",
+        "@opentelemetry/exporter-trace-otlp-http": "^0.214.0",
         "@opentelemetry/sdk-trace-node": "^2.2.0",
         "@radix-ui/react-alert-dialog": "^1.1.15",
         "@radix-ui/react-collapsible": "^1.1.12",
@@ -77,7 +77,7 @@
         "nanoid": "^5.0.0",
         "negotiator": "^1.0.0",
         "next": "^16.0.7",
-        "ollama-ai-provider-v2": "^3.0.0",
+        "ollama-ai-provider-v2": "^2.0.0",
         "pako": "^2.1.0",
         "prism-react-renderer": "^2.4.1",
         "react": "^19.1.2",
@@ -108,7 +108,7 @@
     },
     "devDependencies": {
         "@anthropic-ai/tokenizer": "^0.0.4",
-        "@biomejs/biome": "2.4.13",
+        "@biomejs/biome": "2.4.10",
         "@playwright/test": "^1.57.0",
         "@tailwindcss/postcss": "^4",
         "@tailwindcss/typography": "^0.5.19",
@@ -127,7 +127,7 @@
         "cross-env": "^10.1.0",
         "electron": "^39.2.7",
         "electron-builder": "^26.0.12",
-        "esbuild": "^0.28.0",
+        "esbuild": "^0.27.2",
         "eslint": "9.39.4",
         "eslint-config-next": "16.1.6",
         "husky": "^9.1.7",

packages/mcp-server/package-lock.json

@@ -521,9 +521,9 @@
             }
         },
         "node_modules/@types/node": {
-            "version": "24.12.2",
-            "resolved": "https://registry.npmjs.org/@types/node/-/node-24.12.2.tgz",
-            "integrity": "sha512-A1sre26ke7HDIuY/M23nd9gfB+nrmhtYyMINbjI1zHJxYteKR6qSMX56FsmjMcDb3SMcjJg5BiRRgOCC/yBD0g==",
+            "version": "24.12.0",
+            "resolved": "https://registry.npmjs.org/@types/node/-/node-24.12.0.tgz",
+            "integrity": "sha512-GYDxsZi3ChgmckRT9HPU0WEhKLP08ev/Yfcq2AstjrDASOYCSXeyjDsHg4v5t4jOj7cyDX3vmprafKlWIG9MXQ==",
             "dev": true,
             "license": "MIT",
             "dependencies": {
@@ -2062,9 +2062,9 @@
             }
         },
         "node_modules/zod": {
-            "version": "4.4.1",
-            "resolved": "https://registry.npmjs.org/zod/-/zod-4.4.1.tgz",
-            "integrity": "sha512-a6ENMBBGZBsnlSebQ/eKCguSBeGKSf4O7BPnqVPmYGtpBYI7VSqoVqw+QcB7kPRjbqPwhYTpFbVj/RqNz/CT0Q==",
+            "version": "4.3.6",
+            "resolved": "https://registry.npmjs.org/zod/-/zod-4.3.6.tgz",
+            "integrity": "sha512-rftlrkhHZOcjDwkGlnUtZZkvaPHCsDATp4pGpuOOMDaTdDDXF91wuVDJoWoPsKX/3YPQ5fHuF3STjcYyKr+Qhg==",
             "license": "MIT",
             "funding": {
                 "url": "https://github.com/sponsors/colinhacks"