feat: terminal startup command and container tools

- Add startup_command field to ToolType model and API
- Execute startup command before interactive shell in terminal sessions
- Add tmux and ranger to OpenCode container spec
- Update Tool Workshop UI with startup_command input for terminal types
- Add backend tests for startup_command CRUD operations
- Sync specs: tool-terminal, tool-types-definition, opencode-web-server
- New spec: tool-terminal-startup-command

Quality gates: Frontend typecheck/lint passed. Backend tests blocked by environment (Python/Docker not available).

OpenSpec: terminal-startup-and-container-tools

openspec/specs/tool-types-definition/spec.md

@@ -18,6 +18,7 @@ The system SHALL provide a `ToolType` model to store tool definitions.
   - `dockerfile_template`: Dockerfile string
   - `definition_type`: string — "compose" or "dockerfile"
   - `required_variables`: list of required template variables
+  - `startup_command`: optional text — command to run before interactive shell for terminal sessions
   - `is_builtin`: boolean flag for system-defined types
   - `created_at`/`updated_at`: timestamps
 
@@ -39,6 +40,7 @@ The system SHALL provide REST API endpoints for tool type management.
 - AND validates `requires_port` is boolean
 - AND validates the compose template YAML (if definition_type is "compose")
 - AND validates all required variables are present in template
+- AND accepts optional `startup_command` field
 - AND returns 201 Created with the new tool type
 
 #### Scenario: Get tool type
@@ -51,10 +53,14 @@ The system SHALL provide REST API endpoints for tool type management.
 - GIVEN an admin user
 - WHEN they PUT /api/tool-types/{id} with valid data
 - THEN the system updates the tool type
-- AND validates `interface_type` is "web" or "terminal" if provided
-- AND re-validates the compose template
+- AND accepts optional `startup_command` field
 - AND returns 200 OK with updated tool type
 
+#### Scenario: Get tool type includes startup command
+- GIVEN an authenticated user
+- WHEN they GET /api/tool-types/{id}
+- THEN the response includes `startup_command` if set
+
 #### Scenario: Delete tool type
 - GIVEN an admin user
 - WHEN they DELETE /api/tool-types/{id}