fix: use auto_impl to simplify trait implemention for (&, Box, Arc)

[hanabi1224]

Summary of changes

Changes introduced in this pull request:

Reference issue to close (if applicable)

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Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

Outside contributions

• I have read and agree to the CONTRIBUTING document.
• I have read and agree to the AI Policy document. I understand that failure to comply with the guidelines will lead to rejection of the pull request.

Summary by CodeRabbit

• Chores
  • Added a new build dependency.
  • Internal code refactored to reduce boilerplate implementations across multiple modules while preserving all existing functionality.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: b8b2c0e3-dc43-4601-ab51-c221381e86ad

📥 Commits

Reviewing files that changed from the base of the PR and between c7d9ba6 and 4108dff.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (5)

• Cargo.toml
• src/db/blockstore_with_read_cache.rs
• src/db/car/forest/index/mod.rs
• src/db/mod.rs
• src/libp2p_bitswap/store.rs

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Walkthrough

This change introduces the auto_impl crate as a dependency and applies the #[auto_impl] macro attribute to multiple traits across the codebase. Manual blanket trait implementations for Arc and reference types are replaced with automatic macro-generated implementations, eliminating boilerplate code while maintaining identical trait behavior.

Changes

Cohort / File(s)	Summary
Dependency Addition Cargo.toml	Added auto_impl = "1" dependency to enable procedural macro-based trait implementations.
Blockstore Trait Refactoring src/db/blockstore_with_read_cache.rs	Added #[auto_impl::auto_impl(&, Arc)] to BlockstoreReadCache; added new put() method; removed manual blanket Arc implementation.
Writable Trait Refactoring src/db/car/forest/index/mod.rs	Added #[auto_impl::auto_impl(&)] to Writable trait; added associated constant LEN: u64; removed manual blanket reference implementation for &T.
Database Traits Refactoring src/db/mod.rs	Added #[auto_impl::auto_impl(&, Arc)] to five traits (SettingsStore, EthMappingsStore, PersistentStore, HeaviestTipsetKeyProvider, BlockstoreWriteOpsSubscribable); removed corresponding manual blanket Arc implementations.
Bitswap Store Traits Refactoring src/libp2p_bitswap/store.rs	Added #[auto_impl::auto_impl(&, Arc)] to BitswapStoreRead and BitswapStoreReadWrite; removed manual blanket Arc implementations; added PhantomData import.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• fix: support large index in forest car #6690: Modifies the Writable trait in src/db/car/forest/index/mod.rs—shares trait modifications with this PR.
• fix: make Writable trait async and remove the write_via_buf bridge function #6688: Changes the Writable trait async interface and related implementations in the same module.
• fix: remove write_cache from ForestCar and PlainCar #5860: Modifies PersistentStore trait implementations, one of the traits refactored in this PR.

Suggested reviewers

• LesnyRumcajs
• sudo-shashank
• akaladarshi

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: refactoring trait implementations to use the auto_impl crate for automatic implementations of (&, Box, Arc) instead of manual blanket implementations.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch hm/auto-impl

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch hm/auto-impl

📝 Coding Plan

• Generate coding plan for human review comments

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[LesnyRumcajs]

I like it