v1.9.0

Added

Copy a line reference — L line-select mode

With the content pane focused (or zoomed), press L to enter line-select mode:

• A marker appears on the top visible source line. j/k (or ↑/↓) move it; hold Shift (J/K, or Shift+↑/↓) to extend a selection.
• Enter — or a double-click — copies the repo-relative reference to the clipboard over OSC 52, the same path as y/Y:
  • a single line → src/app.rs:42
  • a range → src/app.rs:42-58
• A mouse click places the marker; a double-click copies. Esc exits.
• Entering from a rendered-markdown or diff view first switches that file to the line-numbered source view, since line numbers only map there.
• L stays focus-gated: with the tree focused it still performs the tree's horizontal scroll (unchanged).
• Correct under the w wrap toggle — the marker, mouse click, and copied reference map through the wrapped layout, so they land on the right source line.

Read-only, zero new dependencies.

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Also in this release: internal test hardening so the full CI matrix (including windows-latest) is green — two hostile-filename tests that can't run on Windows are now unix-gated, with no loss of sanitizer coverage.