chore: add notes about deleting partitions and testing sd cards

knowledge base/f3.md

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+# Fight Flash Fraud
+
+Tool to test flash cards' capacity and performance.
+
+1. [TL;DR](#tldr)
+1. [Further readings](#further-readings)
+   1. [Sources](#sources)
+
+## TL;DR
+
+It fills tested devices with pseudorandom data, then checks they return the same data on reading.
+
+<details>
+  <summary>Setup</summary>
+
+```sh
+brew install 'f3'
+docker pull 'peron/f3'
+port install 'f3'
+```
+
+</details>
+
+<details>
+  <summary>Usage</summary>
+
+```sh
+# Test drives
+# Destroys stored data
+sudo f3probe --destructive --time-ops '/dev/sdb'
+docker run -it --rm --device '/dev/sdb' 'peron/f3' f3probe --destructive --time-ops '/dev/sdb'
+```
+
+</details>
+
+<!-- Uncomment if used
+<details>
+  <summary>Real world use cases</summary>
+
+```sh
+```
+
+</details>
+-->
+
+## Further readings
+
+- [Codebase]
+
+### Sources
+
+- [Documentation]
+
+<!--
+  Reference
+  ═╬═Time══
+  -->
+
+<!-- In-article sections -->
+<!-- Knowledge base -->
+<!-- Files -->
+<!-- Upstream -->
+[codebase]: https://github.com/AltraMayor/f3
+[documentation]: https://fight-flash-fraud.readthedocs.io/en/stable/
+
+<!-- Others -->

snippets/check sd cards.sh

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+#!/usr/bin/env sh
+
+# Test drives
+# Destroys stored data
+sudo f3probe --destructive --time-ops '/dev/sdb'
+docker run -it --rm --device '/dev/sdb' 'peron/f3' f3probe --destructive --time-ops '/dev/sdb'

snippets/delete partitions.sh

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+#!/usr/bin/env sh
+
+# Does *not* ask for confirmation
+sfdisk --delete '/dev/sda'
+
+wipefs -a '/dev/sda'