feat: workspaces own their sessions; desktop parity; sidebar and settings cleanup

Workspace sessions (docs/plans/desktop-parity, phases 1-5 and 7):
- sessions.lane_id: a workspace lists only the sessions its panes held,
  stamped by bindRunSession (first writer wins, nested `claude -p`
  excluded); GET /api/sessions?lane=&archived=
- session row state dot, double-click rename, archive (sessions.archived_at,
  hides only); the activity bar's duplicate Sessions tab removed
- Fork beside Resume (--fork-session, Claude only), Ctrl/Cmd+click a live
  session opens it in a second pane, a diff line's comment is pasted into
  the workspace's last-focused pane (lib/panePaste.ts)

dashboard_runs stability:
- a pane's previous run is archived as <pane>@<started_at> instead of being
  overwritten by INSERT OR REPLACE
- a run is flagged abandoned only once its tmux session is gone, at boot and
  on the run-heal beat (panes outlive a server restart)

UI:
- sidebar: no footer, language or theme block; small collapse button in the
  brand corner; version + update check in the connection details modal, a
  status-bar dot while a release is out; language in Settings -> General
- one Switch component for every switch, the themed Checkbox for every
  checkbox (no native checkboxes)

Also: AI Tools catalog trimmed to 10 built-ins (custom-file prompt modes
tested through fixtures), and the workspace plans under docs/plans/ (the
multi-user server plan lives in the AgentHub-Server repo).

docs/DATABASE.md

@@ -212,6 +212,8 @@ CREATE TABLE sessions (
 | `transcript_path` | TEXT | YES | Absolute path to the session's JSONL transcript. Written by `routes/hooks.js` on the first event that carries it (subsequent events no-op via a SQL guard) and read by the periodic compaction sweep — so the sweep touches only active session rows instead of scanning the entire `events` table for `json_extract(data,'$.transcript_path')`. Backfilled once from `events` by the `db.js` migration |
 | `source` | TEXT | NO | Data source this session was captured from. `'local'` for this machine's own Claude Code history (the default); otherwise the `remote_sources.id` of the remote SSH machine it was pulled from. Powers the `sources` query filter on `/api/sessions`, `/api/events`, `/api/agents`, `/api/stats`, and `/api/analytics`, and the `sources` facet on `/api/sessions/facets`. Indexed by `idx_sessions_source` |
 | `tool` | TEXT | NO | The AI coding CLI that produced the session. `'claude'` for every hook-created and imported row (the default); `'codex'` for a session ingested from Codex's rollout journals by `server/lib/codex-usage.js` (see `codex_rollouts`) or created by a Codex hook (`tool: "codex"`, `server/lib/codex-hooks.js`) — a Codex session keeps the status its hooks give it while they are current (its newest event at or after its newest journal write minus two minutes); once they stop (removed, untrusted) the journal decides again. A codex row has no `transcript_path`, and, going by the journal, its `status` is `active` only while one of its journals was written in the last two minutes. `'antigravity'` for an agy CLI conversation, ingested by `server/lib/antigravity-usage.js` (see `antigravity_conversations`) or created by an Antigravity hook (`server/lib/antigravity-hooks.js`); no `transcript_path`, and `active` until it has been quiet — no write to its conversation file (or a non-empty `-wal`) or transcript, no hook event — for ten minutes when it has hook events, two minutes when it has none; it then settles to `completed`, its agents too. The startup cleanup of stale `active` sessions and a workspace purge touch only the matching tool's rows (a purge takes the sessions of the workspace's own `tool`). The Workspace's attach/resume list offers `'claude'` rows only |
+| `lane_id` | INTEGER | YES | The workspace that OWNS the session — the only sessions a workspace lists: the lane whose dashboard pane held it, stamped by `bindRunSession` (`server/routes/hooks.js`) from the hook's `run_id` — first writer wins, a nested `claude -p` excluded. NULL for a session no workspace started (a terminal, an import, a tool with no hooks). No FK: removing a workspace leaves its sessions. Backfilled once from `dashboard_runs`. Indexed by `idx_sessions_lane` |
+| `archived_at` | TEXT | YES | When the user archived the session out of its workspace's lists (`PATCH /api/sessions/:id {archived}`). Hides only — nothing is deleted |
 
 **Constraints:**
 - `status` must be one of the four enum values