HIGH: Upgrade Hono and other dependencies with known vulnerabilities

[Brad-Edwards]

Severity: High (Appsec H4)

`bun audit` found 6 vulnerabilities:

• High: `@hono/node-server` (<1.19.10) — authorization bypass via encoded slashes
• High: `express-rate-limit` (>=8.2.0 <8.2.2) — IPv4-mapped IPv6 bypass
• High: `hono` (<4.12.4) — arbitrary file access via serveStatic
• Moderate: `esbuild` (<=0.24.2) — dev server request exposure
• Moderate: `hono` (<4.12.4) — cookie attribute injection, SSE control field injection

Currently on Hono 4.12.3, needs ≥4.12.4.

Recommendation: `bun update` to upgrade all affected packages.