Fix SFTP panel restoration and Paper Ops contrast

[bifrost0x]

Summary

• preserve the active embedded SFTP target while the full File Manager is open and restore it when the modal closes
• let SFTPFileManager own Escape handling so the source launcher closes before the modal and embedded Files is restored
• keep manual close, active-session changes, and disconnects authoritative during that handoff
• resolve shared WebSSH 2 theme aliases against the active body theme so Paper Ops settings text remains readable
• add focused unit and Playwright regressions for both reported paths and the reviewed Escape sequence

Root cause

Opening the full File Manager dispatched the same event as a manual embedded-SFTP close, so the workspace persisted a closed preference and never remounted the embedded manager body. The page-level Escape handler also closed the lazily created File Manager directly before its own handler could consume Escape for the source launcher, bypassing SFTPFileManager.close() and the embedded restore path.

Separately, the shared --ws2-* aliases were computed on :root before the Paper Ops variables applied on body[data-theme], leaving light Paper surfaces with dark-theme text values.

Validation

• npm run lint:js
• npm run test:js — 286 passed
• npm run vendor:check — 10 assets verified
• Python 3.14 targeted UI suite — 71 passed
• npx playwright test tests/e2e/theme-system.spec.js tests/e2e/session-workspace.spec.js --forbid-only — 20 passed
• independent follow-up diff review — no findings
• git diff --check origin/main...HEAD

Fixes #130
Fixes #131

[chatgpt-codex-connector]

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