Add `--no-wildcard` (`CODER_CONFIGSSH_NO_WILDCARD`) to `coder
config-ssh` that generates an individual `Host` entry per workspace
instead of a single wildcard block (`Host *.coder`).
The wildcard approach cannot be enumerated by third-party SSH clients,
the VS Code Remote-SSH sidebar, or scripts that parse `~/.ssh/config` to
discover hosts. With `--no-wildcard`, each workspace gets its own entry
so those tools work without Coder-specific extensions.
The flag is persisted in the config section header so re-running without
it prompts the user about the option change. Workspaces are fetched with
pagination before writing so the diff shows actual hostnames.
## Manual testing
**Unit tests (no server needed):**
```sh
go test ./cli/ -run TestSSHConfigOptions_writeToBuffer -v
go test ./cli/ -run TestConfigSSH_NoWildcard -v
```
**End-to-end with a dev server:**
1. Build: `go build -o ./coder .`
2. Start dev server in a separate terminal: `./scripts/develop.sh`
3. Log in: `./coder login http://localhost:3000`
4. Create two workspaces
5. Run both variants into temp files:
```sh
./coder config-ssh --no-wildcard --hostname-suffix coder --ssh-config-file /tmp/test-ssh-config --yes
./coder config-ssh --hostname-suffix coder --ssh-config-file /tmp/test-ssh-config-wildcard --yes
diff /tmp/test-ssh-config-wildcard /tmp/test-ssh-config
```
<details>
<summary>Output: <code>--no-wildcard</code></summary>
```
# ------------START-CODER-----------
# This section is managed by coder. DO NOT EDIT.
#
# You should not hand-edit this section unless you are removing it, all
# changes will be lost when running "coder config-ssh".
#
# Last config-ssh options:
# :hostname-suffix=coder
# :no-wildcard=true
#
Host coder.myworkspace
ConnectTimeout=0
StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null
LogLevel ERROR
ProxyCommand <coder> --global-config <config> ssh --stdio --ssh-host-prefix coder. %h
Host coder.myworkspace2
ConnectTimeout=0
StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null
LogLevel ERROR
ProxyCommand <coder> --global-config <config> ssh --stdio --ssh-host-prefix coder. %h
Host myworkspace.coder
ConnectTimeout=0
StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null
LogLevel ERROR
Match host myworkspace.coder !exec "<coder> connect exists %h"
ProxyCommand <coder> --global-config <config> ssh --stdio --hostname-suffix coder %h
Host myworkspace2.coder
ConnectTimeout=0
StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null
LogLevel ERROR
Match host myworkspace2.coder !exec "<coder> connect exists %h"
ProxyCommand <coder> --global-config <config> ssh --stdio --hostname-suffix coder %h
# ------------END-CODER------------
```
</details>
<details>
<summary>Output: wildcard (default)</summary>
```
# ------------START-CODER-----------
# This section is managed by coder. DO NOT EDIT.
#
# You should not hand-edit this section unless you are removing it, all
# changes will be lost when running "coder config-ssh".
#
# Last config-ssh options:
# :hostname-suffix=coder
#
Host coder.*
ConnectTimeout=0
StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null
LogLevel ERROR
ProxyCommand <coder> --global-config <config> ssh --stdio --ssh-host-prefix coder. %h
Host *.coder
ConnectTimeout=0
StrictHostKeyChecking=no
UserKnownHostsFile=/dev/null
LogLevel ERROR
Match host *.coder !exec "<coder> connect exists %h"
ProxyCommand <coder> --global-config <config> ssh --stdio --hostname-suffix coder %h
# ------------END-CODER------------
```
</details>
<details>
<summary>diff wildcard → --no-wildcard</summary>
```diff
8a9
> # :no-wildcard=true
10c11
< Host coder.*
---
> Host coder.myworkspace
17c18
< Host *.coder
---
> Host coder.myworkspace2
21a23
> ProxyCommand <coder> ssh --stdio --ssh-host-prefix coder. %h
23c25,31
< Match host *.coder !exec "<coder> connect exists %h"
---
> Host myworkspace.coder
> ConnectTimeout=0
> StrictHostKeyChecking=no
> UserKnownHostsFile=/dev/null
> LogLevel ERROR
>
> Match host myworkspace.coder !exec "<coder> connect exists %h"
```
</details>
Closes https://github.com/coder/coder/issues/17153 (Phase 1: CLI flag)
Bobby Ho
dcb120d6ab