feat(paths): a file or folder path on screen is a link when it exists (#99)

[Maxaubert]

Closes #99.

A file or folder path on screen is now a link when it exists. It can be relative to the tab's folder (docs/sign-off/rapport.pdf, as Claude writes them) or absolute (C:\...).

What happens:

• Only real paths light up. lib/termPaths finds text that could be a path, taking off sentence punctuation and a :12 line number. Main answers which of those exist from the shell's folder. Only those get the link colour and a pointer.
  • The check is batched, and results are cached per folder. A "no" is forgotten after 15 s, so a file written after its name was printed lights up later.
• A left click opens a file in the app Windows gives it, and a folder in Explorer.
• Anything runnable is never run. An .exe, a script, a shortcut or an installer (isRunnable) is shown selected in Explorer instead.
• The right-click menu reads Open (or Open folder), Show in Explorer, Copy path. Copy path copies the absolute path.
• Prompts are left alone. PS C:\x> and C:\x> would otherwise make every prompt line a link.
• It works in Claude's fullscreen view too, through fix(links): paint links in full-screen programs too, in a calmer blue (#97) #98's painting of the alternate screen.

Safety:

• Main never trusts the page with a path. A click sends the TEXT back, and main resolves it and checks it exists again before doing anything.
• Network (UNC) paths are refused, because a share can stall a stat.
• Under --e2e, main records what it would open (__e2eOpenedPaths) and opens nothing.

Core change, so Prism too:

• A host whose main does not hand registerTermIpc its paths openers paints no paths at all, so nothing is ever painted that a click could not open. That is Prism until it is wired.
• The new optional TermHostConfig.openPath is where Prism will open files inside Prism, as the owner asked. That wiring is a Prism follow-up PR.

The scope line in CLAUDE.md now says that opening a path in its own app is in (the owner's call). Stacked on #98, which must merge first. Core 0.17.0, app 0.20.0. These numbers overlap with the other open PRs, and whichever merges later gets bumped again.

Verified:

• Unit tests: 952 pass. They cover the finder (the owner's screenshot line, Windows paths, URLs left to the link finder, words and flags ignored), main's resolve, exists, open and reveal, the runnable list, and prompts.
• Lint and typecheck pass.
• A new pathLinks e2e in a real pwsh checks all of the following (10 checks):
  • a file, a folder and a .bat that exist are painted, and a missing path is not;
  • a click opens the file and the folder;
  • the .bat is revealed and never opened;
  • a right-click opens nothing;
  • the menu rows are correct;
  • Show in Explorer and Copy path work, and the clipboard is restored afterwards.
• The full e2e suite passes.
• .e2e-shots/path-links.png was checked by eye.

🤖 Generated with Claude Code

https://claude.ai/code/session_01FHHaWKR4M5QtW7Wecyuk4t