feat: workspace aliases, tab groups of split panes, native path picker (v2.1.0)

- /api/workspaces and `agenthub workspace(s)` / `--workspace` as aliases of
  /api/lanes and `agenthub lanes` / `--lane`; old names print one stderr note.
  REPL `help lanes|workspace|workspaces` resolves through the aliases.
- A workspace holds up to ten sessions (slots 0-9); every console tab is a
  group of 1-4 split panes (PaneGroups, agenthub.workspace.paneLayout);
  parseGroups keeps the stored active tab when an earlier one is dropped.
- Browse button beside path fields: POST /api/lanes/pick-path opens the OS
  picker on the server's desktop — loopback only and no forwarding header
  (EREMOTE), a display failure is ENODIALOG not a Cancel, the dialog is
  killed when the request closes, a folder field falls back to the in-app
  browser on any failure.
- Changes rail counts chip, image viewer (/git/raw), status bar session
  counts and per-day cost (`date=` on /api/pricing/cost).
- /agenthub-open and /agenthub-doctor run from the INSTALLED build
  (supersededBy), doctor offers fixes behind two confirmations; plugin-open
  treats a locked bootstrap as non-fatal.
- New-terminal shell waits for the first attach (issue #55).
- repo-onboarding / debug-live-issue skills removed.
- OpenAPI: pick-path, lane/date on /pricing/cost, tool on /run/history,
  /api/workspaces mount.

skills/debug-live-issue/SKILL.md

@@ -1,23 +0,0 @@
----
-name: debug-live-issue
-description: Debug production-like issues in this repository with disciplined evidence gathering. Use when fixing failing workflows, regressions, flaky behavior, or data inconsistencies across hooks, API, DB, websocket, and UI.
----
-
-# Debug Live Issue
-
-Use this workflow for incident-style debugging.
-
-## Steps
-- Capture symptom, expected behavior, and reproducible path.
-- Isolate subsystem first: hook ingestion, API route, DB state, websocket, or UI rendering.
-- Reproduce with minimal surface area.
-- Prove root cause before changing code.
-- Apply minimal fix and re-verify.
-
-## Evidence standards
-- Prefer direct logs, API responses, DB state checks, and deterministic repro steps.
-- Avoid speculative fixes without root-cause evidence.
-- If not fully reproducible, state uncertainty and strongest hypothesis.
-
-## References
-- Investigation template: `references/investigation-template.md`

skills/debug-live-issue/references/investigation-template.md

@@ -1,32 +0,0 @@
-# Investigation Template
-
-## Problem statement
-- Symptom:
-- Expected behavior:
-- First observed:
-- Scope:
-
-## Reproduction
-- Preconditions:
-- Exact steps:
-- Actual result:
-
-## Evidence
-- Logs:
-- API responses:
-- Database observations:
-- Websocket behavior:
-- UI behavior:
-
-## Root cause
-- Confirmed cause:
-- Why it happens:
-
-## Fix
-- Change summary:
-- Why this fix is minimal and safe:
-
-## Verification
-- Commands/tests run:
-- Manual verification:
-- Residual risk:

skills/repo-onboarding/SKILL.md

@@ -1,24 +0,0 @@
----
-name: repo-onboarding
-description: Onboard quickly to this repository. Use when asked to understand architecture, locate ownership, choose the right module, or identify the correct commands and verification strategy before coding.
----
-
-# Repo Onboarding
-
-Use this workflow when a task begins with discovery.
-
-## Steps
-- Read `README.md` and `ARCHITECTURE.md` for system-level context.
-- Identify target layer:
-  - `server/` for API, hooks, DB, websocket
-  - `client/` for UI and routing
-- Select the smallest set of files required to answer the task.
-- Confirm verification commands before implementation.
-
-## Verification defaults
-- Backend: `npm run test:server`
-- Frontend: `npm run test:client`
-
-## References
-- Module map: `references/module-map.md`
-- Command map: `references/command-map.md`

skills/repo-onboarding/references/command-map.md

@@ -1,13 +0,0 @@
-# Command Map
-
-## Root commands
-- `npm run setup`
-- `npm run dev`
-- `npm run build`
-- `npm start`
-- `npm run test:server`
-- `npm run test:client`
-- `npm run install-hooks`
-- `npm run import-history`
-- `npm run clear-data`
-

skills/repo-onboarding/references/module-map.md

@@ -1,15 +0,0 @@
-# Module Map
-
-## Backend
-- `server/index.js`: app composition, startup behavior, periodic maintenance.
-- `server/db.js`: schema and prepared statement ownership.
-- `server/routes/*.js`: endpoint contracts by domain.
-- `server/websocket.js`: WS lifecycle and broadcast behavior.
-
-## Frontend
-- `client/src/pages/`: route-level screens.
-- `client/src/components/`: reusable UI building blocks.
-- `client/src/lib/api.ts`: client API access patterns.
-- `client/src/hooks/useWebSocket.ts`: live update pipeline.
-
-## MCP