[Feature] Per-project resource toggles in config (port of pi config -l)

[ruttybob]

Area: Agent core / Coding agent and CLI / TUI

Problem

prime-agent config only manages global resources. There is no way to give a project its own resource set — a repo that wants a specific skill, prompt, extension, or theme enabled, or a global one disabled, has to either install it globally (leaks into every other project) or hand-edit the project's .prime/agent/settings.json with +pattern/-pattern overrides. The storage layer already supports project scope, but the config TUI never surfaces it, so precedence is opaque and sharing a setup across a team means hand-writing JSON.

Proposed direction

Port pi's config -l UX:

• prime-agent config -l opens the config TUI in project-local mode; Tab switches between a Global pane and a Project pane.
• The Project pane lists top-level resources (extensions, skills, prompts, themes) with a tri-state: inherit (default) / load / unload.
• load/unload write +pattern / -pattern diffs into the project's .prime/agent/settings.json; inherited-from-global entries render dimmed; explicit project overrides win by the existing precedence ranks — resolution semantics unchanged.
• The project settings.json is committable by design (no trust gate).

Alternatives considered

• Hand-editing project settings.json today: works, but you need to know the pattern syntax and precedence ranks, with no feedback on what actually resolves.
• Copying or symlinking resource files into the project: duplicates resources and drifts from installs.
• A project trust gate (pi-style projectTrusted): rejected — the repo has no trust model and the committable settings file is the point.

Additional context

• pi already ships this exact surface (pi config -l, Tab scope switch, tri-state toggles). The port is the config-selector TUI plus a scoped-resolve seam; no storage-layer changes are needed.
• A first cut would keep package-sourced resources global-only: pi's autoload-delta semantics for those would require core resolution changes.
• I have a working port on a branch (two-pane TUI, -l flag, scoped resolution, tests) and can open a PR if invited.