v1.12.1 - Documentation pass

Documentation-only release. Closes the four docs-* rules of the Gold quality scale and fixes one inverted territory description that slipped into the EN README during v1.10.0.

What's new in the README (EN + FR)

Use cases section

Four concrete examples to help new users get started:

• Wiring the integration into the Home Assistant Energy dashboard
• A monthly bill alert automation
• A daily consumption template sensor derived from the meter index
• A long-term statistics-graph card pulling directly from the imported external statistic

Data update section

Explains how the integration interacts with the portal:

• The 1-hour polling interval (matches the portal's own update rhythm)
• The historical backfill from January 2024 (paid once, then incremental)
• The v1.12.0 token caching (steady-state load = 3 HTTP requests per hour per contract)
• What happens on a failed poll

Known limitations section

Six honest caveats users should know about before adopting:

• No real-time data (water meters telemeter once or twice a day)
• Embedded application credentials may rotate without notice
• Provider-territory mapping may shift
• One contract per integration entry
• Historical statistics floor at 2024
• Energy dashboard cost tracking is a flat per-m³ approximation

Bug fix

The EN README's parameters table still described SEM as Marseille intra-muros and SEMM as Métropole Aix-Marseille-Provence — inverted from reality. SEM serves the periphery, SEMM serves Marseille proper. The FR README and the in-app dropdown labels were already correct; only this one cell was stale.

Quality scale

Gold tier coverage went from 6/8 docs-* rules done to 8/8. The only Gold rule still todo is exception-translations (translation keys on errors raised across the HA boundary), which will be addressed in a follow-up.

Advances #14.