[BUG]: Unclosed IndexedDB database connections in github.js cause memory leaks

[Dotify71]

Bug Description

In src/services/github.js, openDB() opens an IndexedDB database connection on every cached API request (cacheGet, cacheSet, cacheClear). However, the returned db handle is never closed once the transaction finishes or encounters an error.

When analyzing an organization with multiple repositories and fetching contributors, issues, and pull requests, hundreds of IDBDatabase connection handles remain open concurrently in the browser tab. This causes memory buildup and can trigger connection limit warnings or block database upgrades.

Steps to Reproduce

1. Open OrgExplorer and analyze an organization with multiple repositories.
2. Open Chrome DevTools -> Application -> Storage -> IndexedDB -> orgexplorer_cache.
3. Observe active database connection handles persisting without closing.

Code Context

In src/services/github.js:

export async function cacheGet(key) {
  try {
    const db = await openDB()
    return new Promise(res => {
      const req = db.transaction(STORE, 'readonly').objectStore(STORE).get(key)
      req.onsuccess = () => {
        const r = req.result
        if (!r || Date.now() - r.ts > TTL_MS) return res(null)
        res(r.v)
        // Missing db.close() cleanup
      }
      req.onerror = () => res(null)
    })
  } catch { return null }
}

By contrast, src/services/cache.js properly handles transaction lifecycles and calls db.close() on completion and error.

Environment Details

• Location: src/services/github.js
• Impacted Browsers: All browsers supporting IndexedDB (Chrome, Firefox, Safari, Edge)

Impact

High - Major feature is broken