feat: add rtk clean command to reset tracking history

[cubicj]

Summary

• Add rtk clean command that clears all token savings records from the SQLite tracking database
• Clears both commands and parse_failures tables, returns count of deleted records

Why

There is no way to reset rtk gain analytics. When users want to start fresh (e.g. after testing, changing workflow, or benchmarking), they must manually delete the SQLite file. rtk clean provides a safe, built-in reset.

Usage

$ rtk clean
Cleared 803 records from tracking history.

$ rtk gain
No tracking data yet.
Run some rtk commands to start tracking savings.

Test plan

• cargo fmt --all && cargo clippy --all-targets && cargo test
• Manual testing: rtk clean output inspected, rtk gain shows empty after clean

Replaces #684 (was based on master instead of develop, causing noisy diff).

[CLAassistant]

All committers have signed the CLA.

[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