Add OpenWhispr easy setup installer and companion files

Single-file bash installer (setup-openwhispr.sh) with distro detection,
dependency installation, STT/AI cleanup provider selection, API key
management, and first-run launch. Includes README, LICENSE (MIT),
CHANGELOG, .gitignore, ShellCheck CI, issue templates, PR template,
and GitHub setup guide.

https://claude.ai/code/session_01XKYC1basxdwtHy71tky7xm

.github/ISSUE_TEMPLATE/distro_report.md

@@ -0,0 +1,33 @@
+---
+name: Distro compatibility report
+about: Report whether the installer works on your distro
+title: "[Distro] "
+labels: distro-report
+assignees: ""
+---
+
+## Distribution details
+
+- **Distro**: (e.g., Pop!_OS 24.04)
+- **Based on**: (e.g., Ubuntu / Debian / Arch / independent)
+- **Architecture**: (x86_64 / aarch64)
+- **Session type**: (X11 / Wayland)
+- **Desktop environment**: (GNOME / KDE / Sway / other)
+
+## Result
+
+- [ ] Script detected distro correctly
+- [ ] OpenWhispr installed successfully
+- [ ] Paste dependencies installed correctly
+- [ ] API keys stored correctly
+- [ ] OpenWhispr launched after install
+
+## Notes
+
+Any issues, workarounds, or suggestions for this distro.
+
+## Terminal output
+
+```
+Paste full script output here
+```