chore: track .pi-map.md and .pi-map.index.md artifacts

Remove the map files from .gitignore so they are committed as project
navigation artifacts, and also unignore them in the sample fixture.
Regenerate all maps so the committed versions reflect the current source.

openspec/changes/archive/2026-06-11-project-map-prompt-injection/.pi-map.index.md

@@ -0,0 +1,26 @@
+# openspec/changes/archive/2026-06-11-project-map-prompt-injection (index)
+dir: openspec/changes/archive/2026-06-11-project-map-prompt-injection
+
+## role
+Archives a completed prompt-injection feature specification that enables runtime injection of project-map artifacts into LLM context with configurable guidance modes and budget controls.
+## parent
+index: openspec/changes/archive/.pi-map.index.md
+map: openspec/changes/archive/.pi-map.md
+## children
+-
+## files
+- apply-progress.md
+- archive-report.md
+- design.md
+- proposal.md
+- spec.md
+- sync-report.md
+- tasks.md
+- verify-report.md
+## links
+index: openspec/changes/archive/2026-06-11-project-map-prompt-injection/.pi-map.index.md
+map: openspec/changes/archive/2026-06-11-project-map-prompt-injection/.pi-map.md
+## workflows
+-
+## dirty
+-