feat: implement docker infrastructure (US-001)

- Add docker-compose.yml with postgres, redis, api, and web services
- Add multi-stage Dockerfile for API (Python 3.11)
- Add multi-stage Dockerfile for web (Node.js 20 + nginx)
- Add Makefile with common development commands
- Add .env.example with all required environment variables
- Add placeholder pyproject.toml and package.json for builds
- Configure health checks for all services
- Setup persistent volumes for postgres, redis, and repos
- Run services as non-root users

openspec/specs/project-management/spec.md

@@ -0,0 +1,69 @@
+# Project Management Specification
+
+## Purpose
+
+Organize repositories into projects for grouping related work.
+
+## Requirements
+
+### Requirement: Project Creation
+
+The system SHALL allow creating new projects.
+
+#### Scenario: Create project
+- GIVEN an authenticated user
+- WHEN they create a project with name and description
+- THEN a project record is created
+- AND the user is set as owner
+
+### Requirement: Project Listing
+
+The system SHALL list all user projects.
+
+#### Scenario: List projects
+- GIVEN an authenticated user
+- WHEN they view the projects page
+- THEN all their projects are listed with associated repositories
+
+### Requirement: Project Updates
+
+The system SHALL support updating project details.
+
+#### Scenario: Update project
+- GIVEN a project owner
+- WHEN they update the name or description
+- THEN the changes are persisted
+
+### Requirement: Project Deletion
+
+The system SHALL support cascading project deletion.
+
+#### Scenario: Delete project
+- GIVEN a project owner
+- WHEN they delete a project
+- THEN all associated repositories are deleted
+- AND all associated SSH keys are removed
+- AND the project record is deleted
+
+### Requirement: Default SSH Key
+
+The system SHALL allow setting a default SSH key per project.
+
+#### Scenario: Set default key
+- GIVEN a project with SSH keys
+- WHEN the owner selects a default key
+- THEN it's used for git operations in that project
+
+## Dependencies
+
+- Database models: Project, User, GitRepository, SSHKey
+- git-repo (for cascading delete)
+- ssh-keys (for default key)
+
+## Quality Gates
+
+- `pytest` must pass
+- `mypy .` must pass
+- `ruff check .` must pass
+- `npm run typecheck` must pass
+- `npm run lint` must pass