make pull packets include the cover

[nahiyankhan]

Category: improvement
User Impact: Every pulled guidance packet now carries the package's unconditional brand context without requiring an agent to remember a special flag.
Problem: gather previously mixed unconditional cover guidance into the selection menu context, while pull returned only selected nodes. A fresh agent receiving a pull could therefore lose the package stance, and selection was influenced by prose that was not itself selectable.
Solution: Make gather a menu-only selection surface and make every successful pull assemble a self-contained packet: resolved cover, clearly sourced fallback when needed, selected nodes, then starting structures. Selection IDs and automatic cover inclusion remain separate in the embed API and local event tape.

Validation:

• pnpm run quality:all: passed
• Test suite: 225 tests passed
• pnpm check:terminology: passed
• Pre-commit and pre-push hooks: passed

Changeset: added as a minor release because gather and pull public contracts change.

ghost Review:

• Not run because this change defines the grounding packet itself; implementation, package, selection-control, and steering-control tests cover the contract directly.

File changes

.changeset/cover-on-pull.md
Records the public gather and pull contract change.

packages/ghost/src/embed/*
Separates cover and fallback from selected nodes, automatically transports the cover on pull, keeps gather menu-only, and exports the new result types.

packages/ghost/src/commands/*
Supports bare pulls, formats self-contained Markdown and JSON packets, preserves selected-ID telemetry, and updates CLI discovery.

packages/ghost/src/observability-events.ts
Records the automatically included cover separately from selected IDs.

packages/ghost/test/*
Covers menu-only gather, cover-first and bare pulls, absent and dangling covers, explicit cover aliases, unknown IDs, ordering, materials, skeletons, telemetry, and public output alignment.

packages/context-control/*
Removes cover prose from selection-model input and updates the benchmark contract and presentation.

packages/steering-control/README.md
Documents that selected pulls now include the cover.

README.md, packages/ghost/README.md, docs/purposes.md, packages/ghost/src/skill-bundle/*
Updates the package model, command workflow, handoff guidance, and host-facing documentation.

Screenshots/Demos: N/A; no visual product surface changed.