chore: remove legacy pcb-sch position-write helpers

[detail-app]

Remove the legacy direct-to-disk position-writing utilities replace_pcb_sch_comments, remove_positions, and the private write_position_block helper from pcb-sch/src/position.rs, along with their three now-orphaned tests. Also drop the tempfile dev-dependency from pcb-sch (only used by the removed tests) and the now-unused std::fs::OpenOptions, std::io::{Seek, Write}, and std::path::Path imports.

These functions had no production callers: their last consumers (the deprecated direct-to-disk fallback in the pcb/savePositions handler and the pcb/removePosition request handler in pcb-zen/src/lsp/mod.rs) were intentionally removed in commit cc41a2e ("Remove legacy LSP position APIs"). Production now uses the atomic edit_position_comments + LSP TextEdit path exclusively, which never writes to disk directly.

History

• Last materially changed July 2026 (ENG-357 Make schematic position edits atomic #943 @akhilles)

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Dead Code PRs can be configured here.

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Note

Low Risk
Dead-code cleanup with no remaining callers; production position updates still go through edit_position_comments and LSP edits.

Overview
Removes unused direct-to-disk schematic position utilities from pcb-sch: replace_pcb_sch_comments, remove_positions, and the private write_position_block, plus related I/O imports.

Also deletes three tests that exercised file writes via tempfile, drops the tempfile dev-dependency from pcb-sch, and updates Cargo.lock. In-memory position editing via edit_position_comments (and LSP TextEdit flows) is unchanged.

^{Reviewed by Cursor Bugbot for commit ef1e493. Bugbot is set up for automated code reviews on this repo. Configure here.}

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[github-actions]

Build Performance

Board	Base (median)	Head (median)	Change
demo/b/Demeter	63ms ±12	63ms ±8	-1.2%
demo/b/DM0001/Governor	83ms ±6	81ms ±8	-2.3%
demo/b/DM0002/Marlow	66ms ±8	65ms ±5	-1.7%
demo/b/DM0003/Bramble	81ms ±5	80ms ±6	-1.0%
demo/b/Feign	58ms ±12	57ms ±8	-1.0%
demo/b/Renfield	60ms ±2	60ms ±9	-0.4%
demo/b/Seward	63ms ±5	63ms ±5	-1.1%
arduino/b/Nano	59ms ±7	60ms ±8	+1.2%
arduino/b/unoQ	188ms ±10	140ms ±7	1.32× ±0.10 faster

_{Measured with hyperfine. Times show median ±stddev.}

[cursor]

Approved: Cursor Bugbot and Cursor Security Agent completed successfully with no findings requiring human review, and this is a small dead-code cleanup (deletions only, no user-facing behavior change). No reviewers were assigned.

  

_{Sent by Cursor Approval Agent: Pull Request Router and Approver}