chore: v2.8.71 — remote clients (company hub), artifacts shared with chosen people, folders and viewable copies, fixes

Remote clients (docs/plans/remote-clients/README.md, B1–B3 for the Claude pool):
- server/hub/ holds the hub-only code (devices, remote sessions, upload ingest,
  LAN gateway), required only in server mode; hub-boundary.test.js keeps local
  code from importing it.
- A local install enrolls with `agenthub remote login` or Settings → AI tools →
  Company hub; the "Company account" AI Proxy (reserved name agenthub.company)
  sends a session through the hub's gateway, which adds a pool account's token —
  no credential reaches the machine. Only those sessions are uploaded, hourly
  and at their end; secret-shaped strings are redacted on the client.
- Gateway refuses: unknown device (401), a message without a session id, an
  unregistered session under AGENTHUB_REMOTE_GATE=block, a user over quota
  (EQUOTA), a purged session (410). Device tokens 90 days, conversations 30.
- New alert rule type remote_unmonitored: a company-account session its device
  never registered; a late registration clears the flag instead.
- The hub imports a session once per upload round (chunks carry `more`),
  not once per chunk.

Artifacts:
- Share an artifact with chosen people (artifact_shares, PATCH sharedWith,
  GET /api/artifacts/people) besides everyone; a "Shared with you" tab.
  Only the owner or an admin sees or edits who it is shared with; audited.
- Folders: each account's own arrangement (agenthub.artifacts.folders pref).
- A claude.ai page keeps a copy viewable without the publishing account: its
  HTML file (and supporting files) snapshotted at publish, or the copy Claude
  saves for a Doc / Slides / Design in artifacts-export/ (a synchronous
  PostToolUse hint hook, scripts/artifact-export-hint.js, admin switch),
  attached to the page at Stop. Viewed in HtmlFrame's sandbox, Markdown, or
  pdf.js (pdfjs-dist 6.4.299, legacy build, loaded only for a PDF).

Fixes:
- tmux: a cached /proc/<pid>/exe of an exited server falls back to PATH's
  tmux (stop the last pane, start again within 10 s failed with ENOENT).
- shelves: a shelf restores beside changes in other files.
- chat: a finished reply ends the turn even with no hook at all.
- Settings → AI tools: profile list display tweaks.

docs/plans/artifacts/README.md

@@ -14,7 +14,7 @@ One place to keep what agents PRODUCE, and (in server mode) to share it:
 | `plugin` | A plugin by marketplace source + name (no files) | picked from the list a marketplace link answers (`POST /api/artifacts/plugin/inspect`), or typed as `name@marketplace` |
 
 - **Local mode:** one personal library, no sharing UI.
-- **Server mode:** every artifact is the OWNER's and private by default. The owner can **Share** it; a shared artifact appears in the **Hub** for every signed-in user. A shared skill or plugin can be **installed** into the viewer's own account.
+- **Server mode:** every artifact is the OWNER's and private by default. The owner can **Share** it with everyone — it appears in the **Hub** for every signed-in user — or with chosen people only (`artifact_shares`; they find it under **Shared with you**). A `page` keeps a viewable copy — its HTML file, or the copy Claude exports of a Doc / Slides / Design (`artifacts-export/`) — so the people it is shared with need no access to the claude.ai account that published it. A shared skill or plugin can be **installed** into the viewer's own account.
 
 ## Rules (binding, same spirit as CLAUDE.md)
 
@@ -22,7 +22,7 @@ One place to keep what agents PRODUCE, and (in server mode) to share it:
 - **Nothing shared runs on the dashboard's origin.** HTML/SVG previews are served under the `/git/raw` headers (`sandbox` CSP + `nosniff`) and shown in a sandboxed iframe; a type that sandbox cannot show (Office files, zip, PDF — the sandbox blocks both a download and the PDF viewer) gets Download only, never a blank Preview. A `page` is only a link out, accepted only as `https://claude.ai/…`.
 - **Installing is the viewer's explicit click, into the viewer's own account only.** For a skill, the hub writes the snapshot's files into `~/.claude/skills/<name>/` of the VIEWER (S3: as their member, through `write-as`). It never overwrites an existing skill without `conflict: replace`, and the old one goes to the trash first. For a plugin, the hub runs `claude plugin marketplace add <source>` + `claude plugin install <name>@<market> --scope user` as the viewer (the `applyPluginBaseline` path). The marketplace source passes an allowlist (`owner/repo` or a `validateRemoteUrl` URL), and no argv comes from the request beyond those two validated values.
 - **Before installing, the dialog lists every file of the skill** (a skill may carry scripts that the viewer's agent will run). Every share, unshare and install is written to `audit_log`.
-- **Visibility follows ownership:** a developer sees their own artifacts plus shared ones; admin/analyst see per `scope.js`, like sessions. Unshare removes an artifact from the Hub but does not uninstall copies others already installed.
+- **Visibility follows ownership:** a developer sees their own artifacts plus those shared with everyone or with them by name; admin/analyst see per `scope.js`, like sessions. Unshare removes an artifact from the Hub but does not uninstall copies others already installed.
 
 ## Data