[sd_storage] Add SD card storage component documentation

[p1ngb4ck]

Adds documentation for the new sd_storage component, which mounts SD cards into the ESP-IDF virtual filesystem via SD-MMC or SPI interface.

Covers:

Configuration variables for both sd_mmc and sd_spi types

Wiring tables for 4-bit SD-MMC, 1-bit SD-MMC, and SPI

All automations: on_mounted trigger, mount/unmount actions, list_files action, is_mounted condition

Depends on the storage base docs PR (feature/storage-base-docs) which adds the Storage Components section to the index.

Related issue (if applicable): fixes

Pull request in esphome with YAML changes (if applicable):

• [sd_storage] Add SD card storage component with SD-MMC and SPI support esphome#17339

Checklist

• I am merging into next because this is new documentation that has a matching pull-request in esphome as linked above.
  or

• I am merging into current because this is a fix, change and/or adjustment in the current documentation and is not for a new component or feature.

• Link added in /src/content/docs/components/index.mdx when creating new documents for new components or cookbook.

New Component Images

If you are adding a new component to ESPHome, you can automatically generate a standardized black and white component name image for the documentation.

To generate a component image:

1. Comment on this pull request with the following command, replacing component_name with your component name in lower_case format with underscores (e.g., bme280, sht3x, dallas_temp):

   @esphomebot generate image component_name
   

2. The ESPHome bot will respond with a downloadable ZIP file containing the SVG image.

3. Extract the SVG file and place it in the /public/images/ folder of this repository.

4. Use the image in your component's index table entry in /src/content/docs/components/index.mdx.

Example: For a component called "DHT22 Temperature Sensor", use:

@esphomebot generate image dht22

Note: All images used in ImgTable components must be placed in /public/images/ as the component resolves them to absolute paths.

[github-actions]

ImgTable blocks are not in alphabetical order

Found 1 ImgTable block(s) with incorrect ordering below Network Protocols.
Each table has at most one Core item (matching the section name, e.g. "Sensor Core" for the Sensor section), pinned first, followed by Template items (names starting with "Template "), then all remaining items sorted alphabetically.

You can fix this automatically by running:

node script/check_component_index.mjs --fix

See the inline suggestions below for the correct order in each section.

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Component index ordering has been fixed — dismissing review.

[p1ngb4ck]

@esphomebot generate image sd_storage

[github-actions]

@p1ngb4ck Committed public/images/sd_storage.svg to this PR and updated the component index.

Artifact: https://github.com/esphome/esphome.io/actions/runs/28547345639/artifacts/8022407462