Add gitt repo and gitt validator CLI groups

[LandynDev]

Part of repo-registration phase 2a (task 2a-7). Stacked on #1668 AND includes #1664's cli/core commit as a cherry-pick (needed both) — after #1664 and the #1665->#1668 stack merge into feature/repo-registration, rebase drops the duplicate commit and this diff collapses to just the new groups.

New top-level groups built on cli/core (reworks closed #1652 onto the contract):

• gitt repo (alias r): register (GitHub name -> numeric id resolution with --id offline override, live price quote in the confirmation panel, --fee-hotkey defaults to the wallet hotkey), list, show, price, set-params, set-label / remove-label, set-branch-patterns, update-name, transfer, deregister. All owner txs coldkey-signed.
• gitt validator (alias v): weights show|set|clear — set takes repo=weight pairs, quantizes to the exact 65535 sum via largest-remainder (mirrors canonicalize_prefs), validates against the active registry at one head hash, hotkey-signed set_basket.
• set-params accepts human units: FP6 params take decimals (maintainer_cut=0.1), on-chain bounds are fetched pre-submit and shown human-formatted on violation; unknown names print the full 26-key name table.
• All commands support --json (canonical envelope), -y, and the standard network/wallet options; repos_contract_address added to gitt config set keys.
• RepoRegistryContractClient gains the 7 owner txs via a shared _owner_tx helper; metadata selectors regenerated (derived — cross-check against the built .contract before deploy, noted in update_metadata.py).

Tests: 36 new CLI tests (id-resolution incl. 404 abort, normalization + validation failures, bounds errors, confirmation gating, tx-revert envelopes); full suite 1159 passed; ruff clean.