chore: narrow dependency default features (futures, tracing-subscriber, tar)

[Jaro-c]

Problem

Three dependencies pull in unnecessary code via default features:

• DEP-003: futures = "0.3" includes an unused thread-pool executor.
• DEP-004: tracing-subscriber default features include regex-automata (67k lines) and nu-ansi-term.
• DEP-005: tar includes xattr support (rustix/linux-raw-sys) which is not needed.

Fix

futures-util = { version = "0.3", default-features = false, features = ["async-await", "sink"] }
tracing-subscriber = { version = "0.3", default-features = false, features = ["env-filter", "fmt", "std"] }
tar = { version = "0.4", default-features = false }

Rename futures import sites to futures_util where needed.