Docs/add german readme de only

[TheJokerArtzzZ]

Summary

Add a full German translation of the project README for German-speaking users.
Keep the original meaning and structure aligned with the English README.
Preserve all commands, flags, paths, and technical identifiers unchanged (translation only for explanatory text).

Test plan

cargo fmt --all && cargo clippy --all-targets && cargo test (not run; docs-only change)
Manual review: verified translation consistency and readability
Verified command examples remain unchanged
Verified PR diff includes only the German README file

Important: All PRs must target the develop branch (not master).
See CONTRIBUTING.md for details.

[CLAassistant]

All committers have signed the CLA.

[TheJokerArtzzZ]

Hi, I already signed the CLA.
It looks like the remaining missing committer is github-actions[bot], which cannot sign it.
Could someone please re-run or manually approve the CLA/workflow check? Thanks!

[aeppling]

Hey

We are cleaning up the codebase and improving the project structure for better onboarding. As part of this effort, PR #826 reorganizes src/ from a flat layout into subfolders.

No logic changes — only file moves and import path updates.

What you need to do

Rebase your branch on develop when receiving this comment:

git fetch origin && git rebase origin/develop

Git detects renames automatically. If you get import conflicts, update the paths:

use crate::git;        // now: use crate::cmds::git::git;
use crate::tracking;   // now: use crate::core::tracking;
use crate::config;     // now: use crate::core::config;
use crate::init;       // now: use crate::hooks::init;
use crate::gain;       // now: use crate::analytics::gain;

Need help rebasing? Tag @aeppling