fix(desktop): convert file:// URLs to HTTP download for remote gateways

[qingshan89]

When the desktop app connects to a remote Hermes gateway, clicking on agent-generated files (artifacts) fails with '打开失败 / Invalid external URL'.

Root cause: The Electron main process receives file:// URLs from the renderer and tries to open them locally via shell.openPath. But the files exist on the remote server, not the local Windows machine, causing the open to fail.

Changes:

• electron/main.cjs: In openExternalUrl(), detect remote mode and convert file:// URLs to HTTP download URLs (api/files/download) before opening.
• src/lib/media.ts: mediaExternalUrl() generates HTTP download URLs with auth token for remote gateways instead of file:// URLs.
• src/app/artifacts/index.tsx: artifactHref() and openArtifact() use mediaExternalUrl() to resolve file paths at click time.
• hermes_cli/web_server.py: Add /api/files/download endpoint that returns managed files as Content-Disposition: attachment downloads.
• hermes_cli/dashboard_auth/public_paths.py: Add /api/files/download to public paths (no auth required, file access already restricted by _resolve_managed_path).

What does this PR do?

Related Issue

Fixes #

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

How to Test

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform:

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

For New Skills

• This skill is broadly useful to most users (if bundled) — see Contributing Guide
• SKILL.md follows the standard format (frontmatter, trigger conditions, steps, pitfalls)
• No external dependencies that aren't already available (prefer stdlib, curl, existing Hermes tools)
• I've tested the skill end-to-end: hermes --toolsets skills -q "Use the X skill to do Y"

Screenshots / Logs

[alt-glitch]

Related: #44538 (same remote-mode file:// problem, routes via the /api/fs/read-data-url fs bridge) and #41111 (broader desktop direct-file-URL handling). This PR takes a different mechanism — a new authenticated /api/files/download Content-Disposition endpoint in web_server.py plus electron-side conversion — so it competes with #44538 rather than duplicating it. Maintainer should pick one mechanism.

[OutThisLife]

Superseded by #46895 — same fix on a clean LF base (your branch carried ~19k lines of CRLF line-ending noise; the real change is ~60 lines). The salvage also keeps /api/files/download auth-gated (accepting the session token via ?token= like the /api/pty WS) instead of adding it to PUBLIC_API_PATHS, which would have exposed managed-file downloads to unauthenticated callers. You're credited via Co-authored-by. Thanks for finding and diagnosing this!

[MumuTW]

Speaking from a community reviewability perspective: the remote desktop file:// artifact problem is real, but this PR should not be reviewed in its current form.

The diff is only 5 files, but it shows ~38k changed lines because large files such as hermes_cli/web_server.py and apps/desktop/electron/main.cjs appear to have been rewritten wholesale, likely due to line-ending or formatting noise. Existing comments also note that this has been superseded by #46895 on a clean LF base, with the real change closer to a small targeted patch.

I would recommend closing this noisy/conflicting branch and continuing with the clean replacement. For this kind of fix, reviewers should only need to inspect the minimal authenticated download route, the Electron/renderer URL conversion, and focused remote-gateway artifact tests — not whole-file rewrites.

[teknium1]

Thanks for identifying the remote-gateway file:// artifact failure. This has already landed through the clean salvage in #46895, with contributor credit preserved.

• Automated hermes-sweeper review verified merged commit c6b0eb4de0e5010a752e312c0577a4d04d2a08a5 is an ancestor of current main and implements authenticated remote download URL generation in apps/desktop/src/lib/media.ts:61.
• Current main provides the managed attachment endpoint at hermes_cli/web_server.py:1949, scopes query-token authentication to that route at hermes_cli/web_server.py:342, and covers it in tests/hermes_cli/test_web_server_files.py:267.
• The salvaged implementation intentionally does not add the endpoint to PUBLIC_API_PATHS; this branch does, which would bypass dashboard authentication for managed-file downloads.

Closing as implemented on main.