feat(esp32-timer-cam): Update timer cam example to be RTSP video streamer

[finger563]

Description

This PR updates the ESP32 TimerCam example from a simple board demo into a full
RTSP video streamer built on the espp::RtspServer component.

The updated example:

• initializes the TimerCam camera and WiFi stack
• starts an RTSP server when the device gets an IP address
• captures OV2640 JPEG frames and streams them over RTSP
• uses the onboard LED breathing helpers to indicate disconnected / connected
  states
• includes memory monitoring and CLI access for runtime inspection

This PR also includes follow-up robustness fixes for the streamer path:

• avoid a potential null dereference by taking a local shared_ptr snapshot of
  rtsp_server before sending frames
• fix JPEG end-of-image validation to safely require a valid 0xFF 0xD9 marker
  and avoid out-of-bounds access on short frames
• abort startup early if camera initialization fails, instead of continuing in a
  partially initialized state

Motivation and Context

This change makes the ESP32 TimerCam example much more useful as a practical
reference application by turning it into a complete RTSP video streaming demo.

It solves a few problems:

• the previous example did not demonstrate the TimerCam as a full RTSP video
  endpoint
• the camera task had a race around rtsp_server lifetime during frame send
• JPEG validation in the capture path was incorrect and unsafe for short frames
• camera initialization failures did not stop the app from continuing into an
  unusable streaming state

How has this been tested?

The updated example was tested by building:

• components/esp32-timer-cam/example

The follow-up safety fixes were also validated by rebuilding the same example
after:

• fixing the RTSP server lifetime handling
• correcting JPEG EOI validation
• gating startup on successful camera initialization

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Hardware (schematic, board, system design) change
• Software change

Checklist:

• My change requires a change to the documentation.
• I have added / updated the documentation related to this change via either README or WIKI

Software

• I have added tests to cover my changes.
• I have updated the .github/workflows/build.yml file to add my new test to the automated cloud build github action.
• All new and existing tests passed.
• My code follows the code style of this project.

[github-actions]

✅Static analysis result - no issues found! ✅

[Copilot]

Pull request overview

Updates the esp32-timer-cam example to act as an RTSP MJPEG video streamer, adding WiFi connectivity, RTSP server setup, and runtime monitoring/CLI tooling.

Changes:

• Reworked the example app to initialize the camera, connect to WiFi, and stream captured JPEG frames over an RTSP server with mDNS.
• Added project configuration (Kconfig) and partitioning defaults to support streaming use-cases (PSRAM, custom partitions).
• Updated the example build configuration to include additional dependencies/components for networking and streaming.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
components/esp32-timer-cam/example/sdkconfig.defaults	Expands default SDK config (PSRAM, stacks, LWIP/WiFi settings, custom partition table).
components/esp32-timer-cam/example/partitions.csv	Adds a custom partition table including a LittleFS partition.
components/esp32-timer-cam/example/main/Kconfig.projbuild	Introduces menuconfig options for RTSP port and WiFi credentials.
components/esp32-timer-cam/example/main/idf_component.yml	Adds Component Manager dependencies for the example (camera, mdns, espp components).
components/esp32-timer-cam/example/main/esp_timer_cam_example.cpp	Implements the RTSP streamer example: camera init, WiFi STA, RTSP server + mDNS, capture loop, and monitoring CLI.
components/esp32-timer-cam/example/CMakeLists.txt	Updates the example build/component inclusion configuration for new dependencies.