Replace local packages/linting with published torrust-linting crate

[josecelano]

Overview

Closes #416

The packages/linting workspace package has been extracted and published to
crates.io as torrust-linting (v0.1.0).
This PR removes the redundant local copy and switches to the published crate.

Changes

Cargo.toml

• Removed "packages/linting" from [workspace] members
• Changed torrust-linting = { path = "packages/linting" } → torrust-linting = "0.1.0"

packages/linting/ (deleted)

• Removed the entire local package directory (15 files)

Documentation updated

• packages/README.md — removed local linting section; updated library crates example to use crates.io version
• docs/codebase-architecture.md — updated workspace packages listing
• docs/contributing/linting.md — updated linting framework reference
• docs/contributing/testing/quality/coverage.md — updated linting package location
• .github/skills/dev/git-workflow/run-linters/skill.md — updated link
• .github/skills/dev/git-workflow/run-linters/references/linters.md — updated framework architecture section

Verification

• cargo build — passes (downloads torrust-linting v0.1.0 from crates.io)
• cargo test — 416 passed, 0 failed
• All pre-commit checks pass (linters, E2E infrastructure, E2E deployment)
• No source code changes required — the published API is identical to the local package

Specification

See docs/issues/416-replace-local-linting-with-published-crate.md

[josecelano]

ACK 91b3961