feat(cli): add --all flag to uninstall and config unset commands

[appcypher]

Summary

• Add bulk operation support for tool uninstall and tool config unset commands via --all flag
• Enable removing all installed tools or all configuration in a single command
• Add confirmation prompts for destructive bulk operations to prevent accidental data loss
• Remove redundant config reset command in favor of unified config unset --all syntax

Changes

• lib/commands.rs: Add --all and -y/--yes flags to Uninstall and ConfigCommand::Unset variants; remove ConfigCommand::Reset; update help examples
• lib/handlers/tool/config_cmd.rs: Rewrite config_unset to handle multiple keys and --all modes; add unset_tool_keys, unset_tool_all_keys, and unset_all_tools functions; add load_config_from_path helper; add confirmation prompts using Continue? [y/N] pattern
• lib/handlers/tool/registry.rs: Update remove_tools to accept all and yes parameters; add logic to fetch all installed tools when --all is used; add confirmation prompt
• bin/tool.rs: Update dispatch to pass new all and yes parameters

Test Plan

• Run cargo build to verify compilation
• Test tool uninstall --help shows new --all and -y flags
• Test tool config unset --help shows updated syntax
• Verify tool config reset is no longer recognized (should suggest unset)
• Test tool uninstall without args shows error asking for --all
• Test tool config unset without args shows appropriate error
• Test tool config unset bash without keys shows error about --all