style: use f-strings consistently instead of concatenation

fix: use sqlite3.Error instead of Exception in rollback handler

fix: update test parameter name type -> model_type

refactor: consolidate startswith calls into tuple

refactor: move imports to module level

docs: add docstrings to tool execute methods

style: remove unnecessary f-string prefixes in filesystem.py

perf: remove redundant .keys() calls in commands.py

types: add -> None return hint to tool __init__ methods

types: add -> None return hint to provider and agent __init__ methods

types: add -> None return hint to MCP __init__ methods

types: add -> None return hint to channel __init__ methods

style: use ... instead of pass in abstract method bodies

style: use ... instead of pass in abstract methods

refactor: use slice [::-1] instead of list(reversed())