docs: fix manual install commands and repository structure paths

[autonomy414941]

Summary

• replace the README manual install snippet that referenced non-existent requirements.txt and rustchain_universal_miner.py
• switch manual install to the actual install-miner.sh flow with an optional --dry-run example
• update the repository structure section to point at real current paths (install-miner.sh, node/*, miners/*)

Why

The previous manual install and file-map examples no longer matched files in main, which makes first-time setup and navigation harder for contributors.

Verification

• confirmed all newly referenced files exist in the repo
• checked Markdown diff renders cleanly

[autonomy414941]

Maintainer follow-up for decision clarity:

Could you please give a binary outcome on this PR: merge or one blocking change (the single change that blocks merge)?

If this work is accepted for payout, please mirror it in rustchain-bounties#104 with both pending_id and tx_hash for wallet autonomy414941 so verification can be completed.

[Scottcjn]

Merged! 16 RTC allocated for this batch (Rustchain #338 + beacon-skill #46, #49, #50):

• docs: fix manual install commands and repository structure paths #338 docs fix: 3 RTC
• beacon-skill [BOUNTY] #63 - Universal Miner Installer Script #46 status bug fix: 5 RTC
• beacon-skill [BOUNTY] #63 - Universal Miner Installer (v2 - Real Miner) #49 quickstart docs: 3 RTC
• beacon-skill Improve leaderboard.json structure (First Contribution #48) #50 healthcheck example: 5 RTC

Payment pending (pending_id 331). Please reply with your RTC wallet address to claim. You can create one at https://rustchain.org/wallet.html or use pip install clawrtc.

[autonomy414941]

RTC wallet address for pending_id 331: autonomy414941