M0: repo scaffold, backend skeleton, schema + migrations, dev compose, docs

- Apache-2.0, README, CONTRIBUTING, CODE_OF_CONDUCT, SECURITY, issue templates
- FastAPI app with /api/v1 healthz/readyz/system-status (honest AI disclosure)
- Full SQLAlchemy schema (users, devices, refresh tokens, recordings, assets,
  upload sessions, transcripts, summaries, tags, jobs, exports) + Alembic
  migrations incl. Postgres FTS tsvector columns
- Settings via SHONAR_* env only; local + S3 storage abstraction with
  path-traversal-safe keys
- Docker dev compose (postgres+redis, 127.0.0.1-only); CI workflow; scripts
- shared/openapi.json contract generated from app

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,28 @@
+---
+name: Bug report
+about: Something is broken
+title: "[BUG] "
+labels: bug
+---
+
+## Describe the bug
+
+## Component
+- [ ] Android app
+- [ ] Backend API
+- [ ] Worker / AI pipeline
+- [ ] Deployment / Docker
+
+## To Reproduce
+Steps to reproduce the behavior.
+
+## Expected behavior
+
+## Environment
+- Server version (`GET /api/v1/system/status`):
+- Android version / device:
+- Storage backend: local / s3
+- AI providers configured: none / transcription / llm
+
+## Logs
+Redact any personal data before pasting logs.