Skip link detection on the active prompt and prompt prefix (#199)

[dakra]

Summary

• In tty Emacs, the link-keymap text property's RET binding hijacks the actual return key when the cursor sits on a linkified cell (e.g. a path inside a typed cd src/main.rs). The shell never sees RET — issue After adding a command on the shell, I need a trailing space before return executes the command #199.
• Renderer marks OSC 133 B..C cells with a new ghostel-input text property. ghostel--detect-urls now skips ghostel-prompt always (shell-generated decoration) and skips ghostel-input only on the cursor's line — historical typed commands stay clickable.
• Hot-loop perf: cursor's line is captured once as a (bol . eol) cons; the per-match skip check is O(1) instead of line-number-at-pos (O(pos)).

Test plan

• make -j4 all: 39 zig + 103 native + 219 elisp, all green.
• New tests added — verified each fails on main first, passes after the fix:
  • ghostel-test-detect-urls-skips-active-input (elisp): historical input/URL → linkified; active input/URL → skipped; intra-line partial skip; prompt prefix never linkified.
  • ghostel-test-osc133-input-text-property (native): cells between OSC 133 B and C carry ghostel-input; prompt prefix does not.
  • ghostel-test-osc133-input-wide-char-boundary (native): wide CJK input takes 1 Emacs char of ghostel-input; the spacer-tail produces no Emacs char and doesn't extend the region.
• Bench (make bench-quick, 10 iters × 512KB URL/path-heavy data) — within run-to-run noise vs main. The skip-check optimization protects against the worst case (large scrollback × many matches per redraw).
• Live-verified in *ghostel* (zsh shell integration): typing echo ghostel.el is not clickable while typing; after RET, output ghostel.el is clickable; scrolling back to the historical command line, the path inside echo ghostel.el is also clickable; the cwd shown by the prompt prefix is never clickable.

Caveats

• The fix relies on cell-level OSC 133 B..C, which ghostel's bash/zsh/fish integration emits. Shells that emit only OSC 133 A fall back to the row-level ghostel-prompt and lose the historical-input-clickable benefit (the active prompt is still RET-safe).
• TUIs that don't emit OSC 133 (Claude Code, REPLs, etc.) are unaffected — there's no semantic signal for ghostel to use. Fix would need to come from upstream.

[Copilot]

Pull request overview

This PR addresses issue #199 where, in tty Emacs, linkified text can steal the RET keybinding while the cursor is on the actively edited prompt line. It adds a semantic “user input” marker from the renderer and updates the Elisp URL/file detection to avoid linkifying the active input while keeping historical input linkified.

Changes:

• Add a ghostel-input text property (set by the Zig renderer for OSC 133 B..C input cells).
• Update ghostel--detect-urls to always skip ghostel-prompt and to skip ghostel-input only on the active prompt line (with an O(1) per-match check).
• Add Elisp + native-focused tests covering active-input skipping and wide-char input boundaries.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
lisp/ghostel.el	Adds skip predicate and active-line bounds to avoid linkifying active prompt input.
src/render.zig	Tracks per-row input character range and applies ghostel-input property during insert/styling.
src/emacs.zig	Adds pre-interned symbol for ghostel-input so the native module can set the property.
test/ghostel-test.el	Adds regression tests for active-input URL detection skipping and OSC 133 input property behavior.

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