Detect bare relative and punctuation-wrapped file paths (#107)

[dakra]

Summary

• Fixes File detection regex misses bare relative paths #107 — ghostel--detect-urls now linkifies compiler-output-style paths the old \(?:\./\|/\)…:[0-9]+ regex missed: bare relative paths with a / (Rust retroact-macros/src/lib.rs:43:4, Go pkg/foo/bar.go:12:5, TS src/Button.tsx:17), and paths wrapped in punctuation (Python tracebacks (/home/user/x.js:17:5), [path:N], backtick/quote-wrapped).
• Captures optional :column; ghostel--open-link moves the cursor to that column when present.
• New ghostel-file-detection-regex defcustom exposes the pattern. Bare filenames without a / (e.g. main.go:12) are intentionally not matched by default — relying on file-exists-p alone for those risks stat'ing every word:digits token on slow or network filesystems. Users can opt in via the defcustom.
• Per-scan hash memoizes file-exists-p for repeated paths (Rust --> blocks, Python tracebacks).

Performance

Despite matching strictly more patterns, PTY throughput on URL-heavy output improved:

5 MB cat through PTY	Plain ASCII	URL-heavy
ghostel (main)	70 MB/s	44 MB/s
ghostel (this PR)	70 MB/s	56 MB/s (+27%)
ghostel (no detect)	70 MB/s	70 MB/s
vterm	34 MB/s	27 MB/s

The old regex had no leading anchor and retried a full path scan at every / in URL text. The new regex anchors on whitespace or common path-wrapper punctuation (([{<\'"`) and uses non-backtracking character classes, so the match-attempt count drops sharply on URL-dense output.

README benchmark numbers were also refreshed to current hardware (M4 Max, Emacs 31) as part of this PR.

Test plan

• make test — all 115 elisp tests pass, including 5 new cases:
  • bare relative path (existing file → link; nonexistent → skip)
  • paren-wrapped path (Python traceback style) matched
  • bare filename without / skipped (false-positive protection)
  • custom ghostel-file-detection-regex opts into broader matching
  • fileref:PATH:LINE:COL round-trips through ghostel--open-link
• make bench — url-heavy throughput up 27%, plain unchanged
• Exercise interactively: run cargo check in a ghostel buffer, click through to the files

[Copilot]

Pull request overview

Updates Ghostel’s plain-text link detection to recognize more compiler/traceback-style file:line[:col] references (including bare relative paths with / and punctuation-wrapped paths), and to jump to the reported column when present.

Changes:

• Add customizable ghostel-file-detection-regex and update ghostel--detect-urls to use it, including per-scan file-exists-p memoization.
• Extend fileref: handling in ghostel--open-link to support optional :col.
• Add tests/bench inputs and refresh README benchmark numbers.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
ghostel.el	Introduces configurable file detection regex, memoized existence checks, and :col support when opening fileref: links.
test/ghostel-test.el	Adds ERT coverage for new file detection patterns and :col cursor positioning.
bench/ghostel-bench.el	Expands benchmark URL/path generator with new path formats to reflect updated detection.
README.md	Updates benchmark results to current measurements/hardware.

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