Define per-package default timeout constants and remove `DEFAULT_TIMEOUT` from `torrust-tracker-configuration`

[josecelano]

Goal

Replace the shared DEFAULT_TIMEOUT constant in packages/configuration with per-package
timeout constants, each named to reflect the specific operation context of its package.
Remove DEFAULT_TIMEOUT from packages/configuration entirely once all consumers have
defined their own constant.

Background

DEFAULT_TIMEOUT is a Duration constant (Duration::from_secs(5)), defined in
packages/configuration/src/lib.rs. It is not used within the configuration package
itself — it exists solely for other packages to import.

A single generic timeout shared across the entire workspace is too coarse-grained. Each
package performs a different kind of network operation:

• packages/tracker-client: UDP socket connect/send/receive
• packages/axum-http-tracker-server: HTTP request processing via Tower's TimeoutLayer
• packages/udp-tracker-server (tests): UDP client connections in contract tests
• console/tracker-client: network checking (UDP, HTTP, health checks) in a CLI tool

Each package should own its timeout default with a name that reflects its specific context.
Sharing a constant from the configuration crate creates an unnecessary coupling — packages
that have no other reason to depend on torrust-tracker-configuration are forced to do so
solely for a timeout value.

This issue is a subissue of EPIC #1669 (Overhaul: Packages).

Scope

For each of the 4 consumer packages, in order:

1. packages/tracker-client: evaluate usage, define local constant(s), update the one import site, drop torrust-tracker-configuration if it is the only remaining reason for the dep.
2. packages/axum-http-tracker-server: evaluate usage, define local constant(s), update the one import site. Verify whether torrust-tracker-configuration can be dropped; drop it if so.
3. packages/udp-tracker-server (test file): evaluate usage, define local constant(s) in the test module, update all 4 inline import sites. Verify whether torrust-tracker-configuration can be dropped from dev-dependencies; drop it if so.
4. console/tracker-client: evaluate usage, define local constant(s) at crate level, update all 6 import sites, drop torrust-tracker-configuration.
5. packages/configuration: once DEFAULT_TIMEOUT has zero consumers across the workspace, remove the constant and its associated use std::time::Duration; import if it becomes unused.
6. Regenerate the workspace coupling report (docs/issues/open/1669-overhaul-packages/workspace-coupling-report.md) by running cargo run -p workspace-coupling.

Per-package evaluation rule: before defining the local constant(s), review how DEFAULT_TIMEOUT is used within the package. If it is used for two or more semantically distinct operations (for example, "sending/receiving data" vs. "waiting for a socket to become readable or writable"), define a separate named constant for each distinct purpose rather than a single generic timeout.

Out of Scope

• Moving DEFAULT_TIMEOUT to packages/clock — superseded by this approach.
• Any API or behaviour changes beyond replacing the import source.
• Changing timeout values — all local constants use the same Duration::from_secs(5).

Implementation Plan

ID	Task	Notes
T1	packages/tracker-client: evaluate DEFAULT_TIMEOUT usage; define local constant(s)	Candidates: DEFAULT_UDP_TIMEOUT
T2	packages/tracker-client: remove use torrust_tracker_configuration::DEFAULT_TIMEOUT	Use local constant(s); cargo build -p bittorrent-tracker-client succeeds
T3	packages/tracker-client: drop torrust-tracker-configuration from Cargo.toml	cargo machete confirms clean
T4	packages/axum-http-tracker-server: evaluate usage; define local constant(s)	Candidates: DEFAULT_REQUEST_TIMEOUT
T5	packages/axum-http-tracker-server: remove use torrust_tracker_configuration::DEFAULT_TIMEOUT	Use local constant(s); drop dep if possible
T6	packages/udp-tracker-server (tests): evaluate usage; define local constant(s)	Review 4 use sites; candidates: DEFAULT_UDP_TIMEOUT
T7	packages/udp-tracker-server (tests): remove all 4 use torrust_tracker_configuration::DEFAULT_TIMEOUT	Drop from dev-dependencies if possible
T8	console/tracker-client: evaluate usage; define local constant(s)	Review 6 use sites across UDP, HTTP, health-check contexts; candidates: DEFAULT_NETWORK_TIMEOUT
T9	console/tracker-client: update all 6 import sites to use the local constant(s)	Remove all use torrust_tracker_configuration::DEFAULT_TIMEOUT imports
T10	console/tracker-client: drop torrust-tracker-configuration from Cargo.toml	cargo machete confirms clean
T11	packages/configuration: remove DEFAULT_TIMEOUT and its Duration import if unused	Zero consumers remaining; cargo build --workspace succeeds
T12	Run cargo build --workspace and cargo test --workspace	Clean build; all tests pass
T13	Run linter all	Exit code 0
T14	Regenerate workspace coupling report	cargo run -p workspace-coupling; updates docs/issues/open/1669-overhaul-packages/workspace-coupling-report.md

Acceptance Criteria

• packages/tracker-client defines local timeout constant(s); no import from torrust_tracker_configuration; torrust-tracker-configuration removed from its Cargo.toml.
• packages/axum-http-tracker-server defines local timeout constant(s); no import from torrust_tracker_configuration.
• packages/udp-tracker-server test file defines local timeout constant(s); no import from torrust_tracker_configuration in tests.
• console/tracker-client defines local timeout constant(s); no file in that package imports DEFAULT_TIMEOUT from torrust_tracker_configuration; torrust-tracker-configuration removed from its Cargo.toml.
• packages/configuration/src/lib.rs no longer defines DEFAULT_TIMEOUT.
• grep -r "torrust_tracker_configuration::DEFAULT_TIMEOUT" . --include="*.rs" returns zero matches.
• cargo build --workspace succeeds with zero errors.
• cargo test --workspace passes with zero failures.
• linter all exits with code 0.
• Workspace coupling report regenerated and committed.

Spec

docs/issues/open/1669-overhaul-packages/ (spec moved from drafts once issue is created)