feat: Support multiple tag filters

[yimsk]

Summary

Support filtering resource lists by multiple tag conditions.

Motivation

--tag and :tag currently support a single tag condition. It would be useful to combine tags for common workflows, such as narrowing EC2 instances to prod bastion hosts.

Example

claws -s ec2 --tag Env=prod --tag Role=bastion
claws -s ec2 --tag Env=prod,Role=bastion
startup:
  tags:
    - Env=prod
    - Role=bastion

Multiple tag conditions should be treated as AND filters.

[yimsk]

Implementation direction proposal:

• Avoid comma-separated tag filters like --tag Env=prod,Role=bastion.
  • AWS tag values can contain commas/spaces depending on service/resource, so delimiter-based parsing would be ambiguous.
• Support repeated CLI flags for multiple filters:
  • claws -s ec2 --tag Env=prod --tag Role=bastion
  • Multiple tag filters should be ANDed.
• Preserve the existing interactive :tag <filter> behavior as replace/single-filter, to avoid changing current UX.
• Add a separate interactive command for append semantics, likely Vim-style:
  • :tag Env=prod => replace active filters with Env=prod
  • :tagadd Role=bastion => append Role=bastion as an additional AND condition
• For startup config, add a list form while keeping the existing singular form for compatibility:
  • startup.tag: Env=prod remains valid
  • startup.tags: [Env=prod, Role=bastion] adds multiple AND filters

This keeps existing behavior compatible and avoids introducing escaping rules for commas/spaces in tag values.