Story: Suggest the next work item to pick up

A new compass command, compass heading, recommends the next logical work item to pick up, ranked by priority. It synthesises signals across the local journal and the other worktrees' journals (the fleet), the state of sprint stories and tasks (in-flight, blocked, ready-to-close, drift), and the available captures in the inbox and next product-backlog buckets, and returns a prioritised, LLM-consumable list of suggestions — each with a score, a one-line rationale for why it is suggested now, and the ids/links needed to act on it. Optional positional keywords steer the ranking (e.g. compass heading compass biases toward compass-related work).

It completes the navigation arc alongside the existing commands:

bearings (where am I?) → heading (where do I go next?) → goto / story new (set off)

• compass heading prints a ranked list of candidate next work items (human-readable by default; -f json for LLM/tooling consumption).
• Signals considered: the local journal and the other worktrees' journals; sprint story/task states (STARTED, BLOCKED, ready-to-close, and sprint drift); inbox captures; next product-backlog captures.
• Each suggestion carries a priority score, a short "why now" rationale, and the id/link needed to act on it (start a task, pull a capture, close a drifted item, etc.).
• Optional positional keywords bias the ranking toward matching items (by tag, title, description, or component) — e.g. compass heading compass ranks compass work higher; multiple keywords combine.
• The output is stable and structured enough for an LLM to act on without re-parsing prose.
• The command is documented with a recipe and placed in the compass command pillars (a decision-support pillar bridging Locate and Goto).