feat: implement repository clone mode with SSH key support

- Add clone_mode and branch fields to tool_instances
- Add ssh_key_id to git_repositories for per-repo SSH key assignment
- Implement host-side git cloning with branch selection (default: main)
- Mount SSH keys into containers for git operations in clone mode
- Add dirty state check on clone-mode instance deletion with confirmation
- Update SessionsPage with mount/clone selector, branch input, SSH key display
- Add SSH key selector to repository creation form
- Add dirty delete confirmation modal with changed files list
- Update API schemas and endpoints for new fields
- Sync delta specs to main specs (git-repo, tool-instances, repo-clone-mode)
- Archive completed OpenSpec change: repo-clone-mode-with-ssh
- Document git requirement for custom tool types

Quality gates: Frontend typecheck and build passed
OpenSpec: repo-clone-mode-with-ssh archived with all tasks complete

openspec/changes/tool-config-management/tasks.md

@@ -1,42 +0,0 @@
-## 1. Database & Models
-
-- [ ] 1.1 Add category and interfaces fields to ToolType model
-- [ ] 1.2 Create ToolConfig model with user/project/tool scopes
-- [ ] 1.3 Create Alembic migrations for tool_types and tool_configs
-
-## 2. Backend - Tool Config API
-
-- [ ] 2.1 Create GET/POST/PUT/DELETE endpoints for tool configs
-- [ ] 2.2 Support global and project-scoped configs
-- [ ] 2.3 Mount configs into containers when starting instances
-- [ ] 2.4 Update start_instance to inject env vars and write files
-
-## 3. Backend - Tool Type Updates
-
-- [ ] 3.1 Update ToolType API to include category and interfaces
-- [ ] 3.2 Update seed data with categories and interfaces
-- [ ] 3.3 Add OpenCode as built-in tool type
-
-## 4. Frontend - Tool Config UI
-
-- [ ] 4.1 Create tool config management page/component
-- [ ] 4.2 Support env var and file config types
-- [ ] 4.3 Show configs per tool type with global/project toggle
-
-## 5. Frontend - Category & Interface Support
-
-- [ ] 5.1 Display tool categories in lists
-- [ ] 5.2 Show interface-appropriate actions (Open for web, Terminal for CLI)
-- [ ] 5.3 Update instance list to check interfaces
-
-## 6. OpenCode Integration
-
-- [ ] 6.1 Create OpenCode compose template
-- [ ] 6.2 Ensure terminal access works
-- [ ] 6.3 Mount repo and configs correctly
-
-## 7. Quality Gates
-
-- [ ] 7.1 Run ruff and mypy
-- [ ] 7.2 Run frontend typecheck and lint
-- [ ] 7.3 Test end-to-end