Rename `torrust-tracker-clock` to `torrust-clock`

[josecelano]

Goal

Rename the Cargo crate torrust-tracker-clock to torrust-clock to reflect that it is a generic, tracker-independent utility that can be used in any Rust project (e.g., torrust-index).

Background

The clock package (packages/clock) provides a mockable time abstraction for deterministic testing. It contains no tracker-specific logic and its usefulness extends beyond this repository — for example, torrust-index already contains copied clock code.

The torrust-tracker- prefix implies a tracker-only scope that does not reflect the crate's actual purpose. The rename:

• Makes the crate identity match its scope.
• Signals to downstream users that it is reusable outside the tracker.
• Prepares it for potential extraction to a standalone repository in a future cycle (see SI-13).

Note: Publishing torrust-clock on crates.io and handling the old name (torrust-tracker-clock) is deferred to SI-13 (extract torrust-clock to standalone repository). At that point torrust-index will also be updated to depend on torrust-clock directly.

This issue is a subissue of EPIC #1669 (Overhaul: Packages) — SI-09.

Scope

In Scope

• Rename the name field in packages/clock/Cargo.toml.
• Update all Cargo.toml files in the workspace that reference torrust-tracker-clock.
• Update all Rust source files using torrust_tracker_clock:: to torrust_clock::.
• Update prose in packages/AGENTS.md, AGENTS.md, docs/packages.md, and packages/clock/README.md.
• Verify the workspace builds and all tests pass.
• Update EPIC Overhaul: packages #1669 Package Inventory and Desired Package State tables.

Out of Scope

• Publishing torrust-clock on crates.io — deferred to SI-13.
• Deprecating/yanking torrust-tracker-clock on crates.io — deferred to SI-13.
• Updating torrust-index to use torrust-clock — deferred to SI-13.
• Moving the crate to a separate repository — see SI-13.
• Changes to the crate's API or behaviour.

Implementation Plan

ID	Task
T1	Rename name in packages/clock/Cargo.toml
T2	Update root Cargo.toml workspace dependency key
T3	Update all 10 dependent package Cargo.toml files
T4	Update Rust source use / path references (torrust_tracker_clock:: → torrust_clock::)
T5	Update prose in packages/AGENTS.md, AGENTS.md, docs/packages.md, packages/clock/README.md
T6	Run cargo build --workspace and cargo test --workspace
T7	Run linter all
T8	Update EPIC #1669 Package Inventory and Desired Package State tables

Dependent packages for T3 (10 files):

• packages/axum-health-check-api-server/Cargo.toml
• packages/axum-http-tracker-server/Cargo.toml
• packages/axum-rest-tracker-api-server/Cargo.toml
• packages/http-protocol/Cargo.toml
• packages/http-tracker-core/Cargo.toml
• packages/swarm-coordination-registry/Cargo.toml
• packages/tracker-core/Cargo.toml
• packages/torrent-repository-benchmarking/Cargo.toml
• packages/udp-tracker-core/Cargo.toml
• packages/udp-tracker-server/Cargo.toml

Acceptance Criteria

• packages/clock/Cargo.toml declares name = "torrust-clock".
• No Cargo.toml file in the workspace references torrust-tracker-clock.
• No Rust source file in the workspace uses torrust_tracker_clock::.
• cargo build --workspace succeeds with zero errors.
• cargo test --workspace passes with zero failures.
• linter all exits with code 0.
• packages/AGENTS.md, AGENTS.md, docs/packages.md, and packages/clock/README.md reflect the new crate name.
• EPIC Overhaul: packages #1669 Desired Package State table lists torrust-clock.

Local Spec

docs/issues/open/1821-1669-09-rename-torrust-tracker-clock-to-torrust-clock.md

Related to #1669