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

apps/api/src/models/tool_type.py

@@ -30,6 +30,7 @@ class ToolType(UUIDPrimaryKeyMixin, TimestampMixin, Base):
         JSON, default=dict, nullable=True
     )
     readiness_probe: Mapped[dict | None] = mapped_column(JSON, nullable=True)
+    startup_command: Mapped[str | None] = mapped_column(Text, nullable=True)
     required_variables: Mapped[list[str]] = mapped_column(JSON, default=list, nullable=False)
     created_by_id: Mapped[uuid.UUID | None] = mapped_column(
         UUID(),