SI-21: Migrate from `bittorrent-primitives` to `torrust-info-hash`

[josecelano]

Goal

Replace the bittorrent-primitives crate dependency with the new torrust-info-hash crate (v0.1.0) across the entire workspace. The InfoHash type originally came from bittorrent-primitives and has now been published as a standalone crate torrust-info-hash from the torrust/torrust-bittorrent monorepo (see torrust/torrust-bittorrent#87 / torrust/torrust-bittorrent#88).

Background

The bittorrent-primitives crate (v0.2.0) is a single-package repository whose sole public type is InfoHash. As part of the broader workspace overhaul (EPIC #1669), the InfoHash type has been migrated to the torrust/torrust-bittorrent workspace as torrust-info-hash v0.1.0 and published to crates.io.

This workspace (torrust/torrust-tracker) currently depends on bittorrent-primitives in 14 Cargo.toml files (13 packages + the root crate for dev-dependencies) — exclusively for the InfoHash type. Replacing it with torrust-info-hash reduces the dependency footprint and moves toward deprecating/archiving the torrust/bittorrent-primitives repository.

Note: the udp-protocol package (torrust-tracker-udp-tracker-protocol) defines its own local InfoHash struct (a newtype over [u8; 20]) and does NOT use bittorrent-primitives. It is not in scope for this migration.

Scope

In Scope

• Replace bittorrent-primitives = "0.2.0" with torrust-info-hash = "=0.1.0" in all workspace Cargo.toml files that use it for InfoHash
• Update all Rust source files: use bittorrent_primitives::info_hash::InfoHash -> use torrust_info_hash::InfoHash
• Update doc comments that reference the old import path (bittorrent_primitives::info_hash::InfoHash)
• Remove bittorrent-primitives from root Cargo.toml dev-dependencies if no longer needed
• Run cargo machete to verify no unused dependencies remain
• Run linter all and full test suite to validate
• Update AGENTS.md if the package table requires changes
• Update project-words.txt with any new technical terms

Out of Scope

• The udp-protocol package's local InfoHash struct — it is unrelated to bittorrent-primitives (see background)
• Migrating any other types — torrust-info-hash only contains InfoHash
• Publishing new crates to crates.io
• Archiving the torrust/bittorrent-primitives repository

Implementation Plan

ID	Status	Task	Notes / Expected Output
T1	TODO	Add torrust-info-hash to root workspace Cargo.toml dependencies section	Add torrust-info-hash version pin for workspace-wide use
T2	TODO	Replace dependency + imports in packages/http-tracker-core	Cargo.toml + all .rs imports and doc comments
T3	TODO	Replace dependency + imports in packages/http-protocol	Cargo.toml + all .rs imports and doc comments
T4	TODO	Replace dependency + imports in packages/primitives	Cargo.toml + all .rs imports and doc comments
T5	TODO	Replace dependency + imports in packages/tracker-core	Cargo.toml + all .rs imports and doc comments
T6	TODO	Replace dependency + imports in packages/tracker-client	Cargo.toml + all .rs imports and doc comments
T7	TODO	Replace dependency + imports in packages/udp-tracker-core	Cargo.toml + all .rs imports and doc comments
T8	TODO	Replace dependency + imports in packages/udp-server	Cargo.toml + all .rs imports and doc comments
T9	TODO	Replace dependency + imports in packages/axum-rest-api-server	Cargo.toml + all .rs imports and doc comments
T10	TODO	Replace dependency + imports in packages/axum-http-server	Cargo.toml + all .rs imports and doc comments
T11	TODO	Replace dependency + imports in packages/swarm-coordination-registry	Cargo.toml + all .rs imports and doc comments
T12	TODO	Replace dependency + imports in packages/torrent-repository-benchmarking	Cargo.toml + all .rs imports and doc comments
T13	TODO	Replace dependency + imports in packages/persistence-benchmark	Cargo.toml + all .rs imports and doc comments
T14	TODO	Replace dependency + imports in console/tracker-client	Cargo.toml + all .rs imports and doc comments
T15	TODO	Replace root dev-dependency + update tests/ imports	Root Cargo.toml + tests/servers/ files
T16	TODO	Remove bittorrent-primitives from all Cargo.toml files	After confirming no remaining references
T17	TODO	Run cargo check --workspace	Verify compilation
T18	TODO	Run cargo machete	Verify no unused dependencies
T19	TODO	Run linter all	Verify linting passes
T20	TODO	Run cargo test --workspace	Verify tests pass
T21	TODO	Update project-words.txt	Add any needed terms
T22	TODO	Update AGENTS.md if needed	If workspace package table changes

Acceptance Criteria

• AC1: All Cargo.toml files use torrust-info-hash = "=0.1.0" instead of bittorrent-primitives = "0.2.0" for InfoHash
• AC2: All Rust source imports use use torrust_info_hash::InfoHash instead of use bittorrent_primitives::info_hash::InfoHash
• AC3: No remaining references to bittorrent-primitives or bittorrent_primitives except the comment in udp-protocol/src/common.rs (which is out of scope)
• AC4: cargo check --workspace exits with code 0
• AC5: cargo machete exits with code 0
• AC6: linter all exits with code 0
• AC7: cargo test --workspace passes
• AC8: project-words.txt is up to date
• AC9: Documentation is updated when behavior/workflow changes
• AC10: Manual verification scenarios are executed and documented (status + evidence)
• AC11: Acceptance criteria are re-reviewed after implementation and reflect actual behavior