chore: track all project map and index files

Add generated .pi-map.md and .pi-map.index.md files across the repository
so the project navigation maps are shared and versioned. These artifacts
are maintained by project_map_init/patch/validate and must be kept in
sync with source edits.

Note: .cache/ remains ignored (added in previous commit).

.opencode/skills/openspec-apply-change/.pi-map.md

@@ -0,0 +1,19 @@
+# .opencode/skills/openspec-apply-change
+dir: .opencode/skills/openspec-apply-change
+
+index: .opencode/skills/openspec-apply-change/.pi-map.index.md
+
+## role
+Provides a spec-driven AI skill that implements tasks from OpenSpec changes by applying structured modifications to a codebase.
+## files
+- SKILL.md | Defines an AI assistant skill for implementing tasks from an OpenSpec change using a spec-driven workflow | dep: openspec CLI, AskUserQuestion tool, filesystem access
+## arch
+Skill-based modular architecture using markdown-defined capabilities with a workflow-driven pattern that separates specification parsing from implementation execution.
+## tags
+skill, defines, assistant, implementing, tasks, openspec, change, spec
+## symbols
+-
+## workflows
+-
+## dirty
+-