chore: replace first-interaction bot with platform-aware templates

.github/ISSUE_TEMPLATE/bug_report.md

@@ -18,11 +18,13 @@ assignees: ""
 ## Environment
 
 - opencode version (`opencode --version`):
-- OS:
-- Shell:
-- Install method: `./install.sh` / manual / other
+- OS and version (macOS / Linux / Windows):
+- Shell (bash, zsh, PowerShell 5.1, PowerShell 7):
+- Install method: `./install.sh` / `install.ps1` / manual / other
 
-## `./install.sh --check` output
+## Install check output
+
+macOS/Linux: `./install.sh --check` — Windows: `.\install.ps1 -Check`
 
 ```text
 paste the output here

.github/PULL_REQUEST_TEMPLATE.md

@@ -5,8 +5,8 @@
 ## Checklist
 
 - [ ] `ruby scripts/validate.rb` passes
-- [ ] `bash -n install.sh scripts/*.sh` passes
-- [ ] `./scripts/smoke-install.sh` passes
+- [ ] macOS/Linux: `bash -n install.sh scripts/*.sh` and `./scripts/smoke-install.sh` pass
+- [ ] Windows: `.\scripts\smoke-install.ps1` passes (CI also runs it on `windows-latest`)
 - [ ] New frontmatter `description` values are quoted when they contain `: `
 - [ ] `team.yaml` references resolve (`agent`, `skill`, profile stage ids)
 - [ ] README updated if a command, flag, agent or stage changed