refactor: consolidate duplicate block-time and fee divisor constants

[fansilas]

Summary

Two numeric constants were defined in more than one place. This collapses each to a single source of truth without any behavior change.

• SECONDS_PER_BLOCK = 12 in allways/cli/swap_commands/helpers.py duplicated SUBTENSOR_BLOCK_SECONDS = 12 already defined in allways/chains.py. Eight CLI modules imported from helpers; they now import the canonical constant
  from chains.py.
• fee_divisor: int = 100 was hardcoded as a default argument in SwapFulfiller.__init__ and SwapVerifier.__init__ while FEE_DIVISOR = 100 already existed in allways/constants.py. Both defaults now reference the constant.
• display_receipt in swap.py had an inline fee_divisor = 100 # 1% fee that drifted from the same source. Replaced with FEE_DIVISOR, matching the existing pattern at swap.py:634 and quote.py:61.

Changes

• allways/cli/swap_commands/helpers.py: drop SECONDS_PER_BLOCK
• allways/cli/swap_commands/{view,post_tx,swap,admin,status,resume,collateral}.py: import SUBTENSOR_BLOCK_SECONDS from allways.chains, rename usages
• allways/cli/swap_commands/swap.py: display_receipt uses FEE_DIVISOR instead of the inline 100
• allways/miner/fulfillment.py: SwapFulfiller default fee_divisor = FEE_DIVISOR
• allways/validator/chain_verification.py: SwapVerifier default fee_divisor = FEE_DIVISOR

Testing

• All 267 tests pass (pytest)
• ruff check allways/ clean
• ruff format --check allways/ clean

No behavior change since FEE_DIVISOR == 100 and SUBTENSOR_BLOCK_SECONDS == 12.
Runtime defaults verified: both SwapFulfiller and SwapVerifier still resolve fee_divisor to 100.

[LandynDev]

Thanks for this, at the time of your contribution we were landing a planned post-V1 cleanup (#46) which consolidated constants. FEE_DIVISOR is single-source in allways/constants.py and block-time constants are no longer duplicated. Great contribution with clearly same vision.