Coder vulnerable to workspace auto-creation via crafted URL parameters without user consent

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7 and 2.30.2, the `dotfiles` registry module passed unsanitized user input to shell commands, allowing arbitrary code execution inside a provisioned workspace. Any user who supplied a crafted `dotfiles_uri` value (for example, one containing shell command substitution such as `$(...)`) could achieve command execution in their own workspace. The Create Workspace page's `mode=auto` deep links amplified this into a one-click attack: an attacker could craft a URL that prefilled `param.dotfiles_uri` and silently provisioned a workspace with the attacker-controlled value, with no explicit user confirmation. In versions 2.29.7 and 2.30.2, input validation was added to the dotfiles module to reject URIs and usernames containing special characters, and the unsafe `eval`/`sh -c` usage was removed. This eliminated the command injection at its source.