feat: command framework + logs migration
- core/framework/flag.sh: flag::define, flag::parse, accessors
- core/framework/hook.sh: hook::on, hook::fire, hook::off, hook::has
- core/framework/help.sh: help::section, command::help::auto
- core/framework/command.sh: command::define, command::route, lazy loading
- core restructure: framework/ + app/ separation
- load_command: directory-based command detection
- command::exists: accepts new-style commands
- command::run: routing for new-style, legacy fallback
- commands/logs/: migrated to new framework
- logs.sh: router + command::define
- show.sh: flag::define + flag::parse, no manual case blocks
- clean.sh: flag::define + flag::parse
- remove.sh: flag::define + flag::parse
- rotate.sh: flag::define + flag::parse
- logs clean: fix dry_run bool to int conversion
- ctx::json_helper: fixed path after core restructure
- PYTHONPATH: exported in app/core.sh