Refactor component terminology to programs in config and manifest

- Updated the terminology from "components" to "programs" across the codebase, including in config loading, saving, and manifest specifications.
- Introduced a new `stacks.py` file to handle lifecycle actions for development stacks, implementing handlers for Python and React Vite stacks.
- Adjusted tests to reflect the new program structure and ensure proper functionality.
- Revised documentation to align with the new terminology and structure, ensuring clarity on the purpose and configuration of programs, services, and jobs.

app/src/lib/labels.ts

@@ -33,7 +33,7 @@ export const STACK_LABELS: Record<string, string> = {
 export const SECTION_HEADERS: Record<string, { title: string; subtitle: string }> = {
   service: { title: "Services", subtitle: "Long-running processes" },
   scheduled: { title: "Scheduled Jobs", subtitle: "Systemd timers" },
-  component: { title: "Components", subtitle: "Software catalog" },
+  program: { title: "Programs", subtitle: "Software catalog" },
 }
 
 export function runnerLabel(runner: string): string {