fix(ci): add ruff.toml, format check, coverage, merge tests.yml

[avinxshKD]

ruff was only checking syntax errors, format was never checked, coverage was installed but never used, and we had two workflows with different dep installs both running pytest. fixed.

• ruff.toml with E+F, legacy dirs excluded
• format check in CI
• tests.yml gone, matrix moved into ci.yml, tensorflow dep dropped
• coverage wired to concore_cli + concore_base
• .pre-commit-config.yaml so it doesn't hit CI in the first place
• bare excepts: fixed in concore_cli/commands/ (status, stop, validate),,. core modules excluded from ruff per maintainer guidance

Fixes #454

[avinxshKD]

Hey @pradeeban @Rahuljagwani, quick update based on your note about avoiding core modules. I’ve excluded the core Python modules from ruff (both lint and format), so CI won’t touch them. Bare-except fixes are scoped to CLI command files only, nothing in core python classes.

Remaining diff is CI wiring plus format cleanup in CLI/tests, which should be safer to review.

Also once this lands, legacy dirs (0mq/, ratc/, demo/ etc.) are still excluded from ruff. Happy to open a follow-up issue to track that cleanup incrementally when you think it's the right time. lmk