feat(webui): session-list detail row with TUI full-mode info

[edwin-zvs]

Summary

Brings the TUI full-view's per-session info to the web UI session list, always on (no compact/full switch on the web):

• Each row gains a muted detail line under the title: model·effort, a context-window mini-gauge with percentage (continuous fill — finer than the TUI's 4-cell bar, same information), activity (live busy Xs timer while running, Xm ago since the last chat message otherwise — same restart-proof semantics as the TUI via last_message_at, falling back to last_event_at), and lifetime tokens. Cost stays excluded, matching the TUI decision.
• Absent data is omitted; sessions reporting nothing fall back to their directory basename. On narrow sidebars the tokens segment shrinks away first, mirroring the TUI's drop order.
• The busy/age text refreshes on the existing status-glyph ticker (SESSION_STATUS_FRAME_MS), so timers count up between daemon events without re-rendering rows.
• Structurally, each list item becomes a title-row + detail column. Two traps dodged: plain flex-wrap pushed the harness label onto the next line instead of truncating long names, and the page already has a generic .row { flex-direction: column } rule — hence the .title-row class.
• Spec 0106 updated: the web list shows the same detail line with the same omission/fallback rules, always on.

(Live capture from a seeded isolated daemon: shell sessions ticking busy Xs, claude/codex/smith rows showing model, gauge, age; tokens shrink away at this narrow width per the drop order.)

Testing

• Verified live in Chrome against a seeded daemon (hot-served worktree assets): layout, truncation behavior, ticking busy timers, no console errors.
• cargo test --workspace green (1764 passed), including the web_smoke e2e against the rebuilt binary with embedded assets.

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