feat(esp_delta_ota): Added pytest for the delta OTA example

[hrushikesh430]

Description

1. Added pytest for the esp https delta OTA example

[hrushikesh430]

@mahavirj PTAL.

[Copilot]

Pull request overview

Adds CI-oriented pytest coverage for the esp_delta_ota/examples/https_delta_ota example by introducing a local HTTPS server mode on-device, a partition to hold the generated patch, and build/test manifest rules to enable the app for ESP32 CI runs.

Changes:

• Added a pytest-based delta OTA flow that generates a patch, writes it to a dedicated patch_data partition, and triggers OTA via a local HTTPS server on the DUT.
• Added CI-test-only local HTTPS server implementation and Kconfig/CMake integration to embed server certs/keys.
• Updated partition table and build-app rules to support/enable CI testing for ESP32.

Reviewed changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
esp_delta_ota/examples/https_delta_ota/tools/requirements.txt	Adds esptool dependency for tooling used by pytest/patch generation.
esp_delta_ota/examples/https_delta_ota/sdkconfig.ci	CI config enabling stdin URL flow, CI test mode, and HTTPS server features.
esp_delta_ota/examples/https_delta_ota/pytest_https_delta_ota.py	New pytest test that generates/writes patch and drives OTA via stdin + local server.
esp_delta_ota/examples/https_delta_ota/partitions.csv	Fixes explicit offsets and adds patch_data partition for CI patch serving.
esp_delta_ota/examples/https_delta_ota/main/tests/test_local_server_ota.h	Declares CI-test server + stdin parsing helpers.
esp_delta_ota/examples/https_delta_ota/main/tests/test_local_server_ota.c	Implements local HTTPS server + stdin parsing to set patch size/url.
esp_delta_ota/examples/https_delta_ota/main/tests/hello_world_esp32.bin	Adds prebuilt target binary used as “new firmware” for delta patch generation.
esp_delta_ota/examples/https_delta_ota/main/tests/certs/servercert.pem	Adds embedded server certificate for DUT local HTTPS server (CI mode).
esp_delta_ota/examples/https_delta_ota/main/tests/certs/prvtkey.pem	Adds embedded private key for DUT local HTTPS server (CI mode).
esp_delta_ota/examples/https_delta_ota/main/main.c	Adds stdin URL mode and CI-test local server startup; switches embedded cert symbol names.
esp_delta_ota/examples/https_delta_ota/main/Kconfig.projbuild	Adds CI-test enable flag and derived “URL from stdin” config.
esp_delta_ota/examples/https_delta_ota/main/CMakeLists.txt	Conditionally includes CI server source and embeds TLS assets.
esp_delta_ota/examples/https_delta_ota/CMakeLists.txt	Updates CMake minimum version and includes esp_eth component.
esp_delta_ota/.build-test-rules.yml	New build/test enablement rules for esp_delta_ota apps (ESP32 only).
.idf_build_apps.toml	Registers esp_delta_ota/.build-test-rules.yml manifest in the root build-apps config.

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[hrushikesh430]

@mahavirj PTAL.