tools: split filesystem into read, write and file_ai ...

- filesystem_read: read, list, find, find_up, grep, info, exists, diff
- filesystem_write: write, append, edit, edit_lines, insert, mkdir, move, copy, delete
- file_ai: ask (was query), edit (was smart_edit)
- paged numbered reads (500 lines / 50 KB), raw copy mode, binary refusal
- nearest-match and numbered-copy hints on failed edits, context after edit
- guards: empty overwrite, non-empty delete, move/copy overwrite
- cross-tool redirects instead of silent wrong-action errors
- legacy 'filesystem' stays for archived sessions (compression, renderers, webclient)
- profiles, prompts, docs and manuals updated; TUI and webclient render the new tools