feat: privacy-first CLI with human-friendly output

[grumbach]

Privacy-first CLI with human-friendly output

No logs by default. A decentralized network client must not leak metadata. Users opt in with -v/-vv/-vvv.

Human-friendly output:

$ ant file upload --public photo.jpg
Connecting to network... done
Approving token spend... done
Uploading photo.jpg (2.0 MB)...
Storing public data map... done

Upload complete!
  Address: c2643c773...
  Chunks:  3
  Size:    2.0 MB
  Cost:    0.2500 ANT (gas: 0.000106 ETH)
  Time:    0.2s

Anyone can download this file with:
  ant file download c2643c773...

Re-upload (already stored):

Upload complete!
  Cost:    free (already stored)

Download:

$ ant file download --datamap photo.datamap -o restored.jpg
Connecting to network... done
Downloading from network...
Download complete!
  File: restored.jpg
  Size: 2.0 MB
  Time: 0.1s

JSON (clean piping):

$ ant --json file upload photo.jpg 2>/dev/null
{"datamap":"photo.datamap","mode":"private","chunks":3,"size":2097152,"storage_cost_atto":"250000000000000000","gas_cost_wei":"106000000000000","elapsed_secs":0.2}

Changes

• -v info, -vv debug, -vvv trace. Default: silent. Replaces --log-level.
• --evm-network defaults to arbitrum-one (was local which always errored without --devnet-manifest)
• -b supports comma-separated addresses: -b 1.2.3.4:10000,5.6.7.8:10000
• Storage cost and gas cost shown after every upload, wired through from EVM receipts
• Cost shows free (already stored) when chunks already exist on network
• Files < 3 bytes get a clear error instead of a cryptic self-encryption crash
• JSON output uses serde structs (not hand-rolled format strings) for safety on all platforms
• Both JSON cost fields are strings for precision safety (u128 loses precision in JS/Python)
• --json works globally for both upload and download
• Progress on stderr, results on stdout (correct for piping)
• stdout flushed before process::exit
• Error format uses Display chain (not Debug) to avoid leaking internal details
• README updated with new output format and examples

Tested locally

12 test cases on a 10-node local devnet: 1-byte file (error), 1KB/1MB/10MB uploads, re-upload (free), public upload, private download with integrity check, JSON upload, JSON download, missing SECRET_KEY error, bad address error, verbose mode.