[Refactor] Remove dead code markers and fix all clippy warnings

[Copilot]

• Understand the issue: Remove #![allow(dead_code)] from src/hook.rs and src/bin/hook.rs and fix all warnings
• Run baseline tests: All tests passing (57 total)
• Run baseline clippy: No warnings currently shown (likely suppressed by allow directives)
• Remove dead code suppression from src/hook.rs
• Remove dead code suppression from src/bin/hook.rs
• Run clippy to identify warnings
• Investigate and fix each warning:
  • StringPool struct (lines 62-85 in hook.rs) - REMOVED (unused except in tests)
  • Args struct in hook.rs (lines 50-58) - REMOVED (duplicated bin/hook.rs, completely unused)
  • MAX_POOL_SIZE constant - REMOVED (only used by removed StringPool)
  • handle_commit method in bin/hook.rs - REMOVED (dead code, functionality duplicated in execute)
  • Unused constants: BUFFER_SIZE and CONTEXT_PREFIX - REMOVED
  • Unused imports: structopt::StructOpt from hook.rs and ai::model::Model from bin/hook.rs - REMOVED
  • Empty test module in hook.rs - REMOVED
• Run automated fixes with cargo fix and cargo clippy --fix - No changes needed
• Verify all tests still pass: ✅ 53 tests pass (removed 4 StringPool tests)
• Verify clippy produces ZERO warnings: ✅ Clean
• Verify cargo build --release succeeds: ✅ Success
• Verify no #![allow(dead_code)] directives remain: ✅ All removed
• Fix CI formatting failure: Applied cargo fmt to resolve extra blank lines

Summary: Successfully removed all dead code suppressions and eliminated 8 pieces of dead code. Fixed CI failure caused by formatting issues where extra blank lines were not following the project's rustfmt rules. All verification criteria now met with zero clippy warnings and proper formatting.

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Refactor] Remove dead code markers and fix all clippy warnings</issue_title>
<issue_description>## Context
Currently src/hook.rs and src/bin/hook.rs have #![allow(dead_code)] directives that mask potential dead code warnings. This needs to be removed and all warnings addressed.

Priority

🔴 CRITICAL - Must be done first before other refactoring

Steps

1. Remove dead code suppression

   # Remove this line from both files:
   # src/hook.rs:1
   # src/bin/hook.rs:1
   #![allow(dead_code)]

2. Run clippy to find issues

   cargo clippy --all-targets --all-features

3. Address each warning

   • For unused private items: Delete if truly unused
   • For unused public items: Add documentation explaining their purpose or remove if obsolete
   • Specifically investigate:
     • StringPool struct in hook.rs lines 62-85 (defined but never used)
     • Args struct in hook.rs lines 50-58 (may duplicate bin/hook.rs)
     • Any test helper functions that are obsolete

4. Run automated fixes

   cargo fix --allow-dirty --allow-staged
   cargo clippy --fix --allow-dirty --allow-staged

Verification Criteria

✅ Pass:

• cargo clippy produces ZERO warnings
• cargo test passes all tests
• cargo build --release succeeds
• No #![allow(dead_code)] directives remain (except with explicit justification comments)
• All dead code either removed or documented as intentionally public API

Estimated Time

2-3 hours

Dependencies

None - this should be done first

Labels

• refactor
• technical-debt
• priority: critical</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #60

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[oleander]

@copilot Failing CI.

[Copilot]

@copilot Failing CI.

Fixed CI failure - the issue was formatting violations (extra blank lines). Applied cargo fmt to resolve. Commit: f0599d6

[Copilot]

Pull Request Overview

This PR removes dead code suppression directives and eliminates all associated dead code to achieve zero clippy warnings. The refactoring focuses on cleaning up unused structs, constants, imports, and test code that were previously masked by #![allow(dead_code)] directives.

• Removed #![allow(dead_code)] suppressions from hook modules
• Eliminated unused structs, constants, imports, and test code
• Fixed formatting issues that caused CI failures