Add GPT 5 Codex and Sonnet 4.5 (#1398)

Fixes #1405 
    
<!-- This is an auto-generated description by cubic. -->

## Summary by cubic
Adds GPT-5 Codex (OpenAI and Azure) and Claude 4.5 Sonnet to the model
options to enable newer coding models and larger contexts. Also
increases Claude 4 Sonnet max output tokens to 32k.

<!-- End of auto-generated description by cubic. -->


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds GPT‑5 Codex (OpenAI/Azure) and Claude 4.5 Sonnet, and increases
Claude 4 Sonnet max output tokens to 32k across providers and tests.
> 
> - **Models**:
>   - **OpenAI**: add `gpt-5-codex` (400k context, default temp 1).
>   - **Anthropic**:
> - add `claude-sonnet-4-5-20250929` (1M context, `maxOutputTokens:
32_000`).
> - update `claude-sonnet-4-20250514` `maxOutputTokens` from `16_000` to
`32_000`.
> - **Azure**: add `gpt-5-codex` (400k context, `maxOutputTokens:
128_000`).
>   - **Bedrock**:
> - add `us.anthropic.claude-sonnet-4-5-20250929-v1:0` (1M context,
`maxOutputTokens: 32_000`).
> - update `us.anthropic.claude-sonnet-4-20250514-v1:0`
`maxOutputTokens` to `32_000`.
> - **E2E tests**:
> - Update snapshots to reflect `max_tokens` increased to `32000` for
`anthropic/claude-sonnet-4-20250514` in engine and gateway tests.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
73298d2da0c833468f957bb436f1e33400307483. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

e2e-tests/snapshots/engine.spec.ts_send-message-to-engine---anthropic-claude-sonnet-4-1.txt

@@ -1,7 +1,7 @@
 {
   "body": {
     "model": "anthropic/claude-sonnet-4-20250514",
-    "max_tokens": 16000,
+    "max_tokens": 32000,
     "temperature": 0,
     "messages": [
       {

e2e-tests/snapshots/gateway.spec.ts_claude-4-sonnet-1.txt

@@ -1,7 +1,7 @@
 {
   "body": {
     "model": "anthropic/claude-sonnet-4-20250514",
-    "max_tokens": 16000,
+    "max_tokens": 32000,
     "temperature": 0,
     "messages": [
       {