feat(web): personal board — private tasks beside the work board

[tym83]

Summary

Attach your own private GitHub Project as a personal board next to the work board. Personal cards get the full aeman experience — zones, sprints, carry-over, the weekly plan — while staying invisible to everyone else.

What

• Me view splits into two panes: Work (unchanged MeBoard) and Personal (an embedded MeBoard: zone bands + stats, no duplicated toolbar/notes chrome). On narrow screens (≤820px) one pane shows at a time with a clamped ‹ › switcher.
• Team view gains an owner-only virtual Personal chip that repoints the whole team machinery (people×zones grid, sprint state, carry-over, weekly plan) at the personal project's no-team group.
• Setup is a small dialog: the owner is pinned to the signed-in login, only the project number is asked; attaching the work board itself is refused, and loading the personal project as the work board detaches the pointer with a visible warning.
• A failing personal board degrades to a dismissible warning and never takes down the work board. "View as" never shows a personal pane. In lock-board mode the feature is disabled entirely (see below).

Why

The Me view is a day plan; real days mix work and personal tasks, but personal tasks must not live on a shared project. A second, user-owned private project gives them a home with zero server changes.

How it holds together

• Privacy is mechanical, not conventional: every GitHub call already runs under the requesting user's token and the board cache is gated per login, so a private personal project is unreadable and uncacheable for anyone else. The pointer to it is a per-login localStorage preference and never reaches the server. The personal pane posts no presence.
• Two instances, no federation: the board machinery is extracted verbatim into useBoardData and instantiated per board — each owns its state, scoped watch socket and server address, so mutations, notes and logs route to the right project by construction. Server, REST API and MCP: zero changes (Go diff is empty).
• Lock-board mode disables the feature: the server pins every request's owner/project to the locked board, so a "personal" request would silently be served the work project. Gated behind one tested helper (personalPaneVisible); a server-side @me-style allowance is a possible follow-up.

Testing

• 37 vitest cases (12 new: pointer persistence, same-project guard, pane clamps, the visibility gate incl. lock-board), typecheck clean, go test ./... green, full Hugo-less SPA build embedded and exercised.
• Live end-to-end against a real server and two sandbox projects: same-project guard both directions, card creation verified to land on the personal project only (checked via gh project item-list on both), personal team mode with carry-over and weekly plan, the narrow-mode switcher, broken-pointer degradation, keyboard isolation between panes.
• Design doc: docs/design/personal-board.md; behaviour rows P1–P10 in docs/design/behavior-matrix.md.

Residual notes

• Cards created in the personal project outside aeman without a self-assign appear in the personal team view (Unassigned column) but not in the Me pane until assigned — MeView filters by assignee, as on any board.
• The pointer survives logout within the same browser profile (the cards themselves never leak — they are token-gated).
• Attaching a public project under your own login is not warned about; the project's privacy remains the user's responsibility. A visibility check via the API is a possible follow-up.
• The 61px horizontal overflow on very narrow screens reproduces on main's plain Me board with any card — pre-existing, not addressed here.