Simplify logging: drop indicatif, use set-once global verbosity

[OzzyCzech]

Resolves #2.

Changes

1. Drop unused indicatif — removed from Cargo.toml; Cargo.lock regenerated (70 lines gone).
2. Set-once global verbosity — new src/log.rs holds an AtomicU8 set once in main and read by log(level, msg). The verbosity parameter is removed from deploy_mutations, execute_uploads, and auto_init.

Invariants preserved

• stderr/stdout split (status logs → stderr, dry-run plan → stdout).
• Quiet suppresses status logs; errors still propagate via Result.
• Atomic read is safe for concurrent upload workers.
• No password logging.

cargo build / clippy --all-targets / test (23 passed) all green.