feat: tool result reducer for relayed tool outputs

[Shifat7]

What changed

Adds reduceToolOutput(output, config) (src/protocol.mjs), applied inside input normalisation before per-turn truncation to function_call_output and custom_tool_call_output items when enableToolResultReducer is on:

• ANSI escapes and progress-bar/install noise stripped; repeated blank lines collapsed.
• Successful shell output keeps its last N meaningful lines (default 20).
• Failed runs keep the first clear error block (assertion diffs, file paths with line/column, failing test names) plus the last N lines (default 80); discontinuities marked with [...].
• Search/grep output capped at 5 matches per file with a +N more matches in <file> note.
• Every reduction ends with an inline marker: [tool output reduced by Hyperagent Codex Bridge: N lines -> M].

User prose and assistant turns are never reduced — only typed tool-output items. Config: enableToolResultReducer (default true), maxSuccessfulCommandLines, maxFailedCommandLines, maxSearchMatchesPerFile.

Why it saves credits

Tool results are re-sent inside every subsequent turn of a tool loop; noisy logs multiply across turns.

Measured locally (synthetic 184-line failing npm test log):

Before: 6,339 chars (184 lines)
After:    204 chars (6 lines) — error block and assertion diff retained

Testing

npm test: 79 pass, 0 fail (3 pre-existing skips). New tests cover ANSI stripping, successful-tail retention, failure-block preservation, per-file search caps, prose immunity, and disable-flag pass-through.