Give each screen its own YAML override that survives updates (0.2.61)

Override YAML on a screen edits <name>.local.yaml, a package loaded after
the shared board package. New profiles get an empty one; an existing
profile is attached on the first save without reformatting the file. The
editor validates YAML, refuses the managed sections and substitutions,
and Save & check runs ESPHome's full validation of the complete profile.

The example uses !extend: ESPHome appends package lists instead of
merging them by id, so a bare id added a second display without a
platform and failed the build. An override is 12 KB at most and a
too-large body answers as JSON instead of a bare 413. The sidecar is
written before the profile includes it, and a symlinked sidecar is
refused. Firmware stays 0.2.52.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

screen_manager/DOCS.md

@@ -26,6 +26,9 @@ After pairing via the HA ESPHome integration, choose the tiles in ESP Screens.
 **Tile settings** has click behavior, larger values and mini-sliders.
 **Screen settings** has brightness and standby. **Inspector** helps with
 missing attributes or an offline screen. New cards require firmware 0.2.0.
+Each screen also has **Override YAML** for a persistent, hardware-specific
+`<screen>.local.yaml` file. It is loaded after the shared package and does not
+replace the managed name, credentials, Wi-Fi, OTA or package connection.
 
 The screen carries the same settings itself (firmware 0.2.44 or newer): hold the top bar for
 about a second and a half, or put the built-in **Settings** card on a page. What is changed