add grep tool formatters

[LasmarKhalifa]

Closes #1027

[LasmarKhalifa]

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• add ls tool formatters #1021
• add find tool formatters #1020
• add grep tool formatters #1019 👈 (View in Graphite)
• add edit tool formatters #1018
• add write tool formatters #1017
• add read tool formatters #1016
• add bash tool formatters #1014
• restructure Pi tool formatting into per-method dispatch with generic fallback #1012
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[mathiusj]

grep formatters are the most heuristic in the stack — a couple of notes.

[mathiusj]

Match/note heuristic is best-effort and will miscount. %r{\A\S+/} treats any line starting with a non-space run + / as a match, and \A(?:\S+:)?\d+: as a line-number hit. Real grep hits that don't carry a path/line prefix (e.g. grep -h, or matched content that doesn't fit either shape) get bucketed as notes and undercount; conversely a note containing an early / counts as a match. Since "3 matches" is shown to the user, a wrong count is a visible lie. It won't break anything, but please add a comment that this depends on Pi's grep output format and is intentionally approximate — so nobody later trusts the count as exact or "fixes" it by tightening the regex without knowing the contract.

[LasmarKhalifa]

The matching was actually done against logs on the Claude side that spanned over a hundred calls to grep! The current matching got it all right, so I actually expect this to be accurate. My suggestion is to keep this as it is and if we ever notice inaccuracies we can always follow up. What do you think?