fix(ssh): preserve successful discovery when the installed-version probe fails #265

What happened

Priority: P2. A successful source-streamed SSH list can become an overall failure and lose its discovered sessions when the separate installed-version probe fails.

Source:

• Remote list aggregation
• Installed-version probe

The listing and remote_installed_version() run inside the same try block. Injecting a successful listing, followed by a probe-only exception, produces exit 1 / ok=false and drops the successful sessions.

What you expected

The installed-version probe is supplementary metadata. Preserve successful discovery even if this second connection or version parsing fails; expose a bounded diagnostic/version-unknown state separately.

Environment

• Python session-peer 1.0.3 / source 817d92ab780f657ec754d40fcf86087b5b01a883.
• macOS arm64, Python 3.13.7; transport/list and secondary probe were mocked.
• The coupling also exists in v1.0.2: this is an existing behaviour to improve, not wholly a new 1.0.3 regression. Stricter 1.0.3 probe validation can expose additional failure cases.
• No real SSH or remote installation was touched.

Discovery output

Synthetic primary listing returned ok=true with one placeholder session. The final host result after probe failure contained only the error, without that session.

Proposed fix and acceptance criteria

• Isolate supplementary version-probe failures from the primary list result.
• Retain sessions, discovery metadata, SSH identity metadata, and requested/resolved host identity.
• Report version-unknown/probe diagnostics without unsanitized host/process data or terminal controls.
• Test probe timeout, invalid version response, and transport failure following successful discovery.
• Preserve genuine primary discovery failures and multi-host partial-failure exit behaviour.
• Keep update --host installation/version verification strict; do not globally weaken remote_installed_version().
• Preserve normal successful and uninstalled-remote output compatibility.

Checked

• Searched existing issues and open PRs.
• Removed sensitive information; values are fixtures.
• Real SSH connectivity and native approval settings were outside this isolated verification.