[UX] oclite: Tool completion should overwrite start line — fix for parallel tools

[randomm]

Problem

When tools run in parallel, the completion line (✓) appears as a NEW line instead of overwriting the start line (◇). This creates noisy output:

◇ bash  remory search "architecture"
◇ bash  remory search "workflow"
◇ bash  remory search "testing"
✓ bash              ← should overwrite line 1, appears as new line
✓ bash              ← should overwrite line 2, appears as new line
✓ bash              ← only this overwrites line 3 (immediately previous)

Root Cause

The code uses a single lastChunkWasToolStart boolean flag. With parallel tools, each new tool_start overwrites this flag, losing the association between tool_end and its original start line.

The \x1b[1A escape sequence only moves up 1 line — but with parallel tools, the correct start line may be N lines back.

Fix: Map-Based Line Tracking

Replace the single flag with a Map that tracks each tools output position:

1. Maintain a lineCount variable incremented on every \n written
2. On tool_start: store toolLineMap.set(toolKey, lineCount)
3. On tool_end: calculate linesBack = lineCount - toolLineMap.get(toolKey)
4. Use \x1b[${linesBack}A\r\x1b[2K to move up the correct number of lines
5. After overwriting, use \x1b[${linesBack}B to move back down

The tool key should be the part ID or a combination of tool name + arguments that uniquely identifies the tool invocation.

Edge Cases

• Tool summary longer than terminal width (line wraps) — truncate to prevent
• Tool_end arrives after other text output (not just more tool_starts) — need to track ALL output lines, not just tool lines
• Tool key collisions — use unique part IDs from the streaming chunks

Acceptance Criteria

• Parallel tool completions overwrite their start lines
• Sequential tool completions still work
• No visual corruption when tools have different line counts between start/end
• Tool lines truncated to terminal width (prevent wrapping)
• bun run typecheck passes
• bun test passes

[randomm]

Fixed in 1fef395 — tool_end overwrites tool_start line via Live Block