feat: add & list commands with deadlock fix

- Add 'add' command: register hosts via flags or interactive prompts
  Supports password/key/both auth, groups, tags, notes, port override
- Add 'list' command: display hosts with filtering and formatting
  Supports --group, --tag filters, --sort, table/json/wide output
- Fix deadlock bug in JSON storage (RLock within Lock)
  Introduced internal list functions that don't lock
  Affects: ListHosts/GetHost/SaveHost/DeleteHost + KeyPair + Snippet
- Add comprehensive tests for add and list commands
- Update PROJECT_STATE.md (Tasks 1-8 complete, ~55% done)

go.sum

@@ -27,6 +27,8 @@ github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S
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+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
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 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/lucasb-eyer/go-colorful v1.3.0 h1:2/yBRLdWBZKrf7gB40FoiKfAWYQ0lqNcbuQwVHXptag=