Quick chats fail to initialize Codex session

### Description

Testing #324360

Quick chats don't work with codex. Looks like it errors because it doesn't get a `workingDirectory`. It works fine when I use codex in a non-quick-chat session.

```
2026-07-06 12:38:33.891 [warning] [Window] [local-agent-host] Eager createSession failed for codex:/2ab615e9-2854-480a-af02-53ca1cfd8f73: Error: Codex requires a working directory; pass `workingDirectory` to createSession
```

### Issue Details

Item|Value
---|---
Issue Category|Bug
Target|Agents Window
VS Code Version|Code - Insiders 1.128.0-insider (86df0e5dc86a78298b5ffce1c6f6793ad79c3e93, 2026-07-06T05:12:47Z)
OS Version|Darwin arm64 25.5.0

System Info

Item|Value
---|---
VS Code Version|Code - Insiders 1.128.0-insider (86df0e5dc86a78298b5ffce1c6f6793ad79c3e93, 2026-07-06T05:12:47Z)
OS Version|Darwin arm64 25.5.0
CPUs|Apple M5 Max (18 x 2400)
GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x106b [Google Inc. (Apple)], DEVICE=0x0000 [ANGLE (Apple, ANGLE Metal Renderer: Apple M5 Max, Version 26.5 (Build 25F71))], DRIVER_VENDOR=Apple, DRIVER_VERSION=26.5 *ACTIVE*
Machine model name: Mac
Machine model version: 17.6
direct_rendering_display_compositor: disabled_off_ok
gpu_compositing: enabled
multiple_raster_threads: enabled_on
opengl: enabled_on
rasterization: enabled
raw_draw: disabled_off_ok
skia_graphite: enabled_on
trees_in_viz: disabled_off
video_decode: enabled
video_encode: enabled
webgl: enabled
webgpu: enabled
webnn: disabled_off
Load (avg)|4, 3, 4
Memory (System)|128.00GB (62.69GB free)
Process Argv|--crash-reporter-id f3441869-abe8-416f-bbd5-01c71ecec52f
Screen Reader|no
VM|0%
User Agent|Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Code-Insiders/1.128.0-insider Chrome/148.0.7778.271 Electron/42.5.0 Safari/537.36
Installation pure|true

Extensions (4)

Name|Identifier|Author|Version
---|---|---|---
ESLint|dbaeumer.vscode-eslint|dbaeumer|3.0.33
Spanish Language Pack for Visual Studio Code|ms-ceintl.vscode-language-pack-es|MS-CEINTL|1.127.2026070501
Jupyter Keymap|ms-toolsai.jupyter-keymap|ms-toolsai|1.1.2
Chat Customizations Evaluations|ms-vscode.vscode-chat-customizations-evaluations|ms-vscode|1.1.2026062409

Theme extensions: 9

A/B Experiments

```
vsliv368:30146709
pythonvspyt551:31249597
nativeloc1:31118317
dwcopilot:31158714
471b6256:31240254
dwoutputs:31242946
copilot_t_ci:31333650
g012b348:31231168
pythonrdcb7:31268811
pythonpcpt1cf:31399617
6518g693:31302842
6abeh943:31336334
envsactivate1:31349248
editstats-enabled:31346256
cloudbuttont:31366566
3efgi100_wstrepl:31403338
cp_cls_t_966_ss:31526232
4je02754:31481634
c3h7c220:31478652
ge8j1254_inline_auto_hint_haiku:31490507
cp_cls_c_1081:31454833
conptydll_true:31485575
ia-use-proxy-models-svc:31446143
e9c30283:31453065
test_treatment2:31471001
46204921:31447328
idci7584:31454084
e3e4d672:31454087
ei9d7968:31462942
nes-extended-on:31455475
89g7j272:31506658
7e884298:31462391
7e187181:31482583
i2gc6536:31472020
52612955:31508042
h08i8180:31475367
ddid_c:31478205
hmra_i5g22:-9
7df3h592:31491241
cp_cls_t_1082:31535311
cc5hd740:31492954
logging_enabled_new:31490725
jb_cp_cls_t_632:31543129
32d76977:31503652
ha629193:31508444
cdk-lw-on:31524445
nes-vscode-team-custom-1:31540236
f9bf7985:31514991
31fi7170_t:31517328
a1ije391_t:31533808
api_cot_ctrl:31509853
g4a0e106:31510899
41836166:31537719
prpt_ctrl:31513638
jbcp_cls_pctr_t:31531130
3f904173:31522231
cp_intellij_c_nes:31533503
jf4hg949:31526829
hide-eh-duplicates:31533831
h561g132:31531228
ah-cli-default-hide-local:31534101
ihg5j128:31534457
f412h606:31540278
b1c25fc8:31539904
max-result-20:31544850
sandbox-ui-on-2:31543161
8dcid693:31544276
```

### Attachments

https://github.com/user-attachments/assets/a3289898-4d9b-4755-8afa-36254af01bef