[Frontend] Paper triage-edit residuals from PR #1995's Codex round: mobile action stacking, Triaged-row edit, filter-change draft, stalled-detail Cancel

[Chris0Jeky]

Codex P2s on PR #1995's pre-fix head, minus the two already fixed there (sibling-edit gate, busy-slot Save). Tracked at the round ceiling.

• Phone layout: the row's third action (Edit) joins a grid that doesn't stack — verify/fix the narrow-width arrangement.
• Triaged captures are editable server-side (New|Failed|Triaged) but the Paper gate stops at New|Failed — an edit could re-open the 'nothing to propose' dead end (fix(frontend): #1944 capture triage states why a blocked action is off and what a decision did #1952 family; deliberate for now, recorded in the PR).
• Switching the Inbox board filter while an editor is open: decide draft fate explicitly (currently follows the leave-list close path).
• A stalled detail GET leaves the loading branch with no Cancel/Close.

Refs: PR #1995, #1951, #1952, tracker #1947.