android: keep session timestamps on one line

[0xSero]

Closes #162.

Root cause

The session row rendered relative time as an unconstrained multiline trailing Text. Long model/runtime metadata or increased font scale could reduce the remaining width enough for Compose to wrap the timestamp one character at a time.

Change

• move time into the second metadata row
• make model/runtime labels yield space and ellipsize
• reserve a minimum timestamp width
• enforce one line, no wrapping, and end alignment
• add a Compose regression at 180dp, 2× font scale, and long metadata

The corresponding iOS metadata row already uses a single line, so this is intentionally Android-only.

Verification

• git diff --check
• static layout review confirms maxLines = 1, softWrap = false, and a reserved minimum width

Remaining acceptance

This machine has no configured Android emulator. The instrumented test and exact rendered row must run under PR CI/emulator, followed by a screenshot or physical-device check with long host/CWD metadata at increased font size. This remains draft until then.

[0xSero]

Mobile CI shared-prep and the full Android job both passed. I intentionally canceled the still-running iOS job because this PR is Android-only and its named remaining gate is installed Android rendering at increased font size; the unrelated iOS cross-build was blocking #221’s clean iOS hermeticity proof. Rerun the complete matrix before readiness if branch policy requires it. The retained Android result is the relevant compilation/test evidence.