Rename decision-mapping skill to wayfinder

## What Renames the in-progress **`decision-mapping`** skill to **`wayfinder`** (invoked `/wayfinder`) and reframes it around the Wayfinder persona. ## Why "Decision map" was jargony and inaccurate — only one of the skill's four ticket types (Grilling) is actually a decision. The reframe gives one coherent leading-word world: you're the **Wayfinder**, charting a route through a **foggy** problem, pushing back the **frontier** by resolving investigation **tickets** one at a time until the way to the goal is clear. ## Changes - Folder + skill `name` → `wayfinder`; invocation examples, `in-progress/README.md` link, and changeset updated to match - Description rewritten around the Wayfinder frame - Pruning pass: unified `node`→`ticket`, bound "the frontier" to the unblocked tickets, dropped the duplicated "one question at a time" (owned by `/grilling`), trimmed intro no-ops - `wayfinding` survives only as the activity gerund ("one per wayfinding effort") Includes a `minor` changeset. 🤖 Generated with [Claude Code](https://claude.com/claude-code)