[AnirudhG07]

Description

This PR refactors IO and FS a lot and improve the overall arrangement

1. FS now has file permissions recipe and some cleaning
2. IO has spawning Tasks, spawning child processes, which was distributed here and there, now properly set
3. Interrupts and deadlocking is added
4. Miscellaneous is now more miscellaneous

things are much better.

Checklist

• My code builds locally with lake build lean-cookbook && lake exe lean-cookbook and checked how it looks locally.
• I have followed the methodology of cooking my recipe using COOKBOOK_GUIDELINES.md.
• I have added my new recipe at appropriate index position(check it if not applicable).

Any other remarks

[Copilot]

Pull request overview

This PR reorganizes the cookbook’s IO and filesystem documentation by splitting previously mixed topics into more focused recipes and adding new coverage for file permissions, task concurrency patterns, process spawning, sleeping, and interrupts.

Changes:

• Replaces older IO recipes with new dedicated pages for spawning tasks, running tasks in parallel, sleeping/async sleep, child processes, and interruption patterns.
• Adds a new filesystem recipe for setting/reading file permissions, and relocates some filesystem snippets (e.g., rename) to more appropriate pages.
• Updates chapter aggregation files (Cookbook/IO.lean, Cookbook/FileSystem.lean) to reflect the new structure and removes obsolete example/config files.

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 14 comments.

Show a summary per file

File	Description
service_config.toml	Removes a previously committed sample TOML config file.
README.md	Updates the repository positioning/intro note.
Cookbook/IO/TasksAndConcurrency.lean	Deletes the old combined tasks/concurrency recipe.
Cookbook/IO/SpawningTasks.lean	Adds a new recipe covering Task spawning, status, and thread IDs.
Cookbook/IO/SpawningChildProcess.lean	Adds a new recipe for IO.Process.run/output/spawn and env vars.
Cookbook/IO/SleepingProcess.lean	Adds a new recipe explaining IO.sleep vs async sleep and .block.
Cookbook/IO/RunningTasksInParallel.lean	Adds a new recipe demonstrating concurrent IO tasks.
Cookbook/IO/ProcessInterrupt.lean	Adds a new recipe on interruptible sleep, promises, and idle waiting.
Cookbook/IO/Miscellaneous.lean	Expands miscellaneous IO content (process exit, compression, deadlocks).
Cookbook/IO/EnvironmentVars.lean	Removes the old environment variables recipe (content moved elsewhere).
Cookbook/IO.lean	Updates IO chapter imports/includes to the new recipe set/order.
Cookbook/Infoview/DisplayingInTheInfoView.lean	Small documentation/formatting edits to the Infoview recipe.
Cookbook/FileSystem/WritingToFile.lean	Adds file rename snippet to the writing-to-file recipe.
Cookbook/FileSystem/RunningAnExternalProgram.lean	Removes the old external program recipe (content moved to IO).
Cookbook/FileSystem/Miscellaneous.lean	Removes the rename snippet from filesystem miscellaneous.
Cookbook/FileSystem/FilePermissions.lean	Adds a new recipe for setting and reading file permissions.
Cookbook/FileSystem.lean	Updates filesystem chapter imports/includes (adds permissions recipe).
Cookbook/DataStructures/TOML/ReadWriteTomlFile.lean	Comments out the round-trip #eval example.
Cookbook/BuildingRecipe.lean	Updates documentation guidance around formatting/errors and html splitting.

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