Incorrect tools names in built-in Agents files

Type: Bug

## Symptom

If you make a copy of the built-in "Explore" agent, its tools array will show as

```yaml
tools: ['search', 'read', 'web', 'vscode/memory', 'github/issue_read', 'github.vscode-pull-request-github/issue_fetch', 'github.vscode-pull-request-github/activePullRequest', 'execute/getTerminalOutput', 'execute/testFailure']
```

Both `github.vscode-pull-request-github/issue_fetch` and `github.vscode-pull-request-github/activePullRequest` show the "Unknown tool" error, despite having the extension installed.
And in fact, the "Explore" agent does NOT have access to the `issue_fetch` and `activePullRequest` tools.

## Cause

That is caused by the fact that their proper id starts with `GitHub.vscode-pull-request-github` (case-sensitive).
This issue has been silenced and hidden by the fix to #304778

## Suggested solution

Modify `DEFAULT_READ_TOOLS` in extensions/copilot/src/extension/agents/vscode-node/agentTypes.ts to have

```ts
'GitHub.vscode-pull-request-github/issue_fetch',
'GitHub.vscode-pull-request-github/activePullRequest',
```

instead of

```ts
'github.vscode-pull-request-github/issue_fetch',
'github.vscode-pull-request-github/activePullRequest',
```

## Similar issue

`github/issue_read` also shows as nonexistent, but I have no idea what it's supposed to be.

VS Code version: Code 1.127.0 (4fe60c8b1cdac1c4c174f2fb180d0d758272d713, 2026-06-30T10:52:33+02:00)
OS version: Windows_NT arm64 10.0.26100
Modes:
Remote OS version: Linux x64 6.8.0-90-generic

System Info

|Item|Value|
|---|---|
|CPUs|Snapdragon(R) X Elite - X1E78100 - Qualcomm(R) Oryon(TM) CPU (12 x 2976)|
|GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x4d4f4351, DEVICE=0x36334330 [Qualcomm(R) Adreno(TM) X1-85 GPU], DRIVER_VENDOR=Qualcomm, DRIVER_VERSION=31.0.133.1 *ACTIVE*
GPU1: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.8521
Machine model name:
Machine model version:
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: disabled_off
trees_in_viz: disabled_off
video_decode: enabled
video_encode: enabled
webgl: enabled
webgpu: enabled
webnn: disabled_off|
|Load (avg)|undefined|
|Memory (System)|31.56GB (15.66GB free)|
|Process Argv|--crash-reporter-id d4b504f0-1e36-4ccf-96e5-6da6c2e2812a|
|Screen Reader|no|
|VM|0%|

|Item|Value|
|---|---|
|Remote|SSH: hu-sbrocard-fra|
|OS|Linux x64 6.8.0-90-generic|
|CPUs|Intel(R) Xeon(R) Gold 6240R CPU @ 2.40GHz (8 x 0)|
|Memory (System)|31.34GB (26.97GB free)|
|VM|100%|
Extensions (53)

Name|Identifier|Author|Version
---|---|---|---
Mermaid Markdown Syntax Highlighting|bpruitt-goddard.mermaid-markdown-syntax-highlighting|bpruitt-goddard|1.8.1
GitHub Repositories|github.remotehub|GitHub|0.64.0
Jupyter Keymap|ms-toolsai.jupyter-keymap|ms-toolsai|1.1.2
Dev Containers|ms-vscode-remote.remote-containers|ms-vscode-remote|0.463.0
Remote - SSH|ms-vscode-remote.remote-ssh|ms-vscode-remote|0.124.0
Remote - SSH: Editing Configuration Files|ms-vscode-remote.remote-ssh-edit|ms-vscode-remote|0.87.0
WSL|ms-vscode-remote.remote-wsl|ms-vscode-remote|0.104.3
Remote Development|ms-vscode-remote.vscode-remote-extensionpack|ms-vscode-remote|0.26.0
Azure Repos|ms-vscode.azure-repos|ms-vscode|0.40.0
Remote Explorer|ms-vscode.remote-explorer|ms-vscode|0.5.0
Remote Repositories|ms-vscode.remote-repositories|ms-vscode|0.42.0
Remote - Tunnels|ms-vscode.remote-server|ms-vscode|1.5.3
vscode-pdf|tomoki1207.pdf|tomoki1207|1.2.2
Claude Code for VS Code|anthropic.claude-code|Anthropic|2.1.199
ty|astral-sh.ty|astral-sh|2026.60.0
Ruff|charliermarsh.ruff|charliermarsh|2026.56.0
cmake-format|cheshirekow.cmake-format|cheshirekow|0.6.11
Doxygen Documentation Generator|cschlosser.doxdocgen|cschlosser|1.4.0
markdownlint|davidanson.vscode-markdownlint|DavidAnson|0.61.2
GitLens — Git supercharged|eamodio.gitlens|eamodio|18.2.0
Syntax Highlighter|evgeniypeshkov.syntax-highlighter|evgeniypeshkov|0.5.0
GitHub Pull Requests|github.vscode-pull-request-github|GitHub|0.154.0
Prettier SQL VSCode|inferrinizzard.prettier-sql-vscode|inferrinizzard|1.6.0
Format Files|jbockle.jbockle-format-files|jbockle|3.4.0
clangd|llvm-vs-code-extensions.vscode-clangd|llvm-vs-code-extensions|0.6.0
Bash IDE|mads-hartmann.bash-ide-vscode|mads-hartmann|1.43.0
Git Graph|mhutchie.git-graph|mhutchie|1.30.0
Container Tools|ms-azuretools.vscode-containers|ms-azuretools|2.4.5
Python Debugger|ms-python.debugpy|ms-python|2026.6.0
Python|ms-python.python|ms-python|2026.4.0
Pylance|ms-python.vscode-pylance|ms-python|2026.2.1
Python Environments|ms-python.vscode-python-envs|ms-python|1.36.0
Data Wrangler|ms-toolsai.datawrangler|ms-toolsai|1.24.2
Jupyter|ms-toolsai.jupyter|ms-toolsai|2026.6.2026061001
Jupyter Keymap|ms-toolsai.jupyter-keymap|ms-toolsai|1.1.2
Jupyter Notebook Renderers|ms-toolsai.jupyter-renderers|ms-toolsai|1.3.0
Jupyter Cell Tags|ms-toolsai.vscode-jupyter-cell-tags|ms-toolsai|0.1.9
Jupyter Slide Show|ms-toolsai.vscode-jupyter-slideshow|ms-toolsai|0.1.6
CMake Tools|ms-vscode.cmake-tools|ms-vscode|1.23.52
C/C++ DevTools|ms-vscode.cpp-devtools|ms-vscode|0.5.13
C/C++|ms-vscode.cpptools|ms-vscode|1.32.2
C/C++ Extension Pack|ms-vscode.cpptools-extension-pack|ms-vscode|1.5.1
Hex Editor|ms-vscode.hexeditor|ms-vscode|1.11.1
Live Preview|ms-vscode.live-server|ms-vscode|0.4.19
Chat Customizations Evaluations|ms-vscode.vscode-chat-customizations-evaluations|ms-vscode|1.0.8
vscode-just|nefrob.vscode-just-syntax|nefrob|0.10.2
autoDocstring - Python Docstring Generator|njpwerner.autodocstring|njpwerner|0.6.1
YAML|redhat.vscode-yaml|redhat|1.23.0
Language Server tools for Copilot|sehejjain.lsp-mcp-bridge|sehejjain|1.0.1
Even Better TOML|tamasfe.even-better-toml|tamasfe|0.21.2
VS Code Counter|uctakeoff.vscode-counter|uctakeoff|3.7.2
vscode-netron|vincent-templier.vscode-netron|vincent-templier|1.1.7
CodeViz Stat|vizzuhq.code-viz-stat|vizzuhq|0.1.4

A/B Experiments

```
vsliv368cf:30146710
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
6abeh943:31336334
envsactivate1:31538736
cloudbuttont:31379625
3efgi100_wstrepl:31403338
839jf696:31457053
ddidtcf:31399634
ec5jj548:31422691
cp_cls_t_966_ss:31526232
4je02754:31466945
c3h7c220:31478652
cp_cls_c_1081:31454833
conptydll_true:31498968
ia-use-proxy-models-svc:31452481
e9c30283:31461165
test_treatment2:31471001
46204921:31447328
idci7584:31464702
e3e4d672:31494082
ei9d7968:31496641
nes-extended-on:31455476
chat:31457767
8hig5102:31480529
89g7j272:31518289
7e187181:31503455
i2gc6536:31499202
52612955:31516516
ghj88844:31499326
h08i8180_copy:31475368
ddid_c:31478207
hmra_i5g22:31518061
7df3h592:31512476
cp_cls_t_1082:31535311
logging_enabled_new:31498466
j0d79568:31499440
jb_cp_cls_t_632:31543129
b1ei0813:31506238
748c7209:31512887
32d76977:31512328
ha629193:31508444
cdk-lw-on:31524445
f9bf7985:31543584
31fi7170_t:31522396
a1ije391_t:31540920
g4a0e106:31529594
41836166:31537719
jbcp_cls_pctr_t:31531130
61138546:31518536
cp_intellij_c_nes:31533503
gf14b233:31526830
nes-curr-leftover-1500:31538366
h561g132:31533256
session_8:31532895
h7dd7680:31543284
ihg5j128:31534457
7g2b5551:31542111

```