chore: regenerate stale .pi-map.md / .pi-map.index.md project maps

Project map had drifted: claimed recharts unused (was used), ObservabilityPage.tsx
exists (refactored to service-tabs/), missed JellyfinNowPlayingWidget +
authentik/backups service types. Regenerate to reflect post-change reality:
new Qbittorrent/LineSeriesChart/Prometheus{Gauge,Mean}Widget files,
service_data.py/qbittorrent_store.py, canonical prometheus-charting +
service-storage specs, archived changes.

frontend/src/lib/.pi-map.index.md

@@ -2,7 +2,7 @@
 dir: frontend/src/lib
 
 ## role
-Provides shared utility functions for the frontend application.
+Provides shared utility functions for the frontend application, specifically Tailwind CSS class merging and conflict resolution.
 ## parent
 index: frontend/src/.pi-map.index.md
 map: frontend/src/.pi-map.md

frontend/src/lib/.pi-map.md

@@ -4,11 +4,11 @@ dir: frontend/src/lib
 index: frontend/src/lib/.pi-map.index.md
 
 ## role
-Provides shared utility functions for the frontend application.
+Provides shared utility functions for the frontend application, specifically Tailwind CSS class merging and conflict resolution.
 ## files
 - utils.ts | Utility function that merges Tailwind CSS classes with proper deduplication and conflict resolution | exp: func:cn(...inputs: ClassValue[]), call:twMerge, call:clsx | dep: clsx, tailwind-merge
 ## arch
-Functional utility module pattern leveraging clsx and tailwind-merge for deterministic CSS class composition.
+Functional utility module pattern using the `clsx` + `tailwind-merge` (cn) convention for deterministic class composition.
 ## tags
 merge, tailwind, cn, call:tw, call:clsx, utils, utility, merges
 ## symbols