cli: display bandwidth/cir as human-readable strings, update help text

[juan-malbeclabs]

Summary of Changes

• --bandwidth and --cir flags in interface create and interface update now require an explicit unit (Kbps, Mbps, or Gbps); bare numbers are rejected
• interface create: --bandwidth and --cir are now optional (no default); omitting them sends 0
• interface list displays bandwidth and CIR as human-readable strings (e.g., 1Gbps) instead of raw u64 values

Diff Breakdown

Category	Files	Lines (+/-)	Net
Core logic	2	+11 / -9	+2
Scaffolding	2	+6 / -6	0
Tests	2	+5 / -0	+5
Docs	1	+1 / -0	+1

Small but impactful UX change: enforces explicit units on bandwidth input and improves readability of list output; tests and changelog updated accordingly.

Key files (click to expand)

• smartcontract/programs/common/src/types/parse_utils.rs — bandwidth_parse now returns an error when no unit is provided; added bandwidth_to_string for human-readable output
• smartcontract/cli/src/device/interface/list.rs — changed bandwidth/cir display fields from u64 to String using bandwidth_to_string()
• smartcontract/cli/src/device/interface/create.rs — bandwidth and cir changed to Option<u64> with no default; help text updated
• smartcontract/cli/src/device/interface/update.rs — updated --bandwidth and --cir help text
• smartcontract/cli/src/validators.rs — added test cases for unit-required validation

Testing Verification

• validate_parse_bandwidth("1000") now returns an error; validate_parse_bandwidth("1Mbps") passes
• Updated table and JSON snapshot assertions in test_cli_device_interface_list to expect formatted strings (1Kbps, 500bps, etc.)
• 206/206 unit tests passing

[vihu]

Just a quick note, there is some backward incompatibility introduced here which we should probably note in the CHANGELOG. Anyone who is using --output json would have got "bandwidth": 1000 now they will see "bandwidth":"1Kbps". It's a minor change but we should flag it.

[juan-malbeclabs]

Right, going back to u64 and I’ll add the formatting for the table.

    #[tabled(display = "crate::util::display_as_bandwidth", rename = "bandwidth")]
    pub bandwidth: u64,

[elitegreg]

LGTM. I typically like doing these with a type that wraps a u64 so you don't have to check the i/o every possible place in the program, it just becomes the default behavior for that type. So struct Bandwidth(u64) with FromStr, Debug, Display, Clone, Copy, PartialEq, BorshSerialize, BorshDeserialize traits should do it. Just something to consider. Not blocking this merge.