SI-5: Deprecate rest-api-core and remove from workspace

[josecelano]

SI-5: Deprecate rest-api-core and remove from workspace

Closes #1943

Summary

After SI-4 migrated the stats context to the contract-first architecture, the rest-api-core package became an empty shell with a single consumer (axum-rest-api-server). This PR:

1. Moves TrackerHttpApiCoreContainer (DI container) into rest-api-runtime-adapter
2. Removes the entire packages/rest-api-core/ directory
3. Updates all import paths across the workspace
4. Removes workspace dependency and deny.toml wrapper rules
5. Removes the crate from the deployment publish workflow
6. Updates all documentation references (AGENTS.md, docs/packages.md)

Changes

Code Changes

• Moved TrackerHttpApiCoreContainer from rest-api-core to rest-api-runtime-adapter/src/container.rs
• Updated 7 import paths across axum-rest-api-server and src/ to use rest_api_runtime_adapter::container
• Added tokio dependency to rest-api-runtime-adapter/Cargo.toml (needed for the container)
• Removed rest-api-core dependency from axum-rest-api-server/Cargo.toml and root Cargo.toml
• Deleted entire packages/rest-api-core/ directory (~1100 lines removed)
• Updated deny.toml — removed rest-api-core from 3 wrapper rules
• Updated .github/workflows/deployment.yaml — removed cargo publish step

Documentation Changes

• Converted issue spec to folder format (ISSUE.md)
• Updated AGENTS.md, packages/AGENTS.md, docs/packages.md
• Added new use-rest-api skill under .github/skills/usage/
• Added manual verification evidence to the issue spec

Verification

• Workspace builds cleanly (cargo check --workspace)
• Pre-commit checks pass
• Pre-push checks pass (full test suite incl. workspace-coupling)
• Manual verification: all API endpoints working correctly (stats, metrics, announce)

[Copilot]

Pull request overview

This PR removes the now-redundant torrust-tracker-rest-api-core crate from the workspace after the contract-first REST API migration, relocating the remaining DI container wiring into rest-api-runtime-adapter and updating workspace references, publishing workflow, and documentation accordingly.

Changes:

• Moved TrackerHttpApiCoreContainer into torrust-tracker-rest-api-runtime-adapter and re-exported it from the crate.
• Updated import paths and Cargo dependencies across the tracker binary and axum-rest-api-server; removed rest-api-core from the workspace, deny wrapper rules, and deployment publishing.
• Updated documentation/issue specs and added a new use-rest-api skill with skill-link markers.

Reviewed changes

Copilot reviewed 30 out of 31 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
src/container.rs	Switches container import to torrust-tracker-rest-api-runtime-adapter.
src/bootstrap/jobs/tracker_apis.rs	Updates REST API container imports (including test module).
share/default/config/tracker.development.sqlite3.toml	Adds skill-link: use-rest-api marker for REST API usage workflow.
packages/rest-api-runtime-adapter/src/lib.rs	Exposes the new container module publicly.
packages/rest-api-runtime-adapter/src/container.rs	New home for TrackerHttpApiCoreContainer wiring.
packages/rest-api-runtime-adapter/Cargo.toml	Adds torrust-tracker-configuration and tokio (sync) for container wiring.
packages/rest-api-core/src/statistics/services.rs	Deleted as part of removing rest-api-core.
packages/rest-api-core/src/statistics/mod.rs	Deleted as part of removing rest-api-core.
packages/rest-api-core/src/statistics/metrics.rs	Deleted as part of removing rest-api-core.
packages/rest-api-core/src/lib.rs	Deleted as part of removing rest-api-core.
packages/rest-api-core/README.md	Deleted as part of removing rest-api-core.
packages/rest-api-core/LICENSE	Deleted as part of removing rest-api-core.
packages/rest-api-core/Cargo.toml	Deleted as part of removing rest-api-core.
packages/axum-rest-api-server/src/v1/routes.rs	Switches REST API container import to runtime-adapter.
packages/axum-rest-api-server/src/v1/middlewares/auth.rs	Adds skill-link: use-rest-api marker in rustdoc header.
packages/axum-rest-api-server/src/testing/environment.rs	Switches REST API container import to runtime-adapter.
packages/axum-rest-api-server/src/server.rs	Switches REST API container import to runtime-adapter (incl. tests).
packages/axum-rest-api-server/src/routes.rs	Switches REST API container import to runtime-adapter.
packages/axum-rest-api-server/Cargo.toml	Drops dependency on torrust-tracker-rest-api-core.
packages/AGENTS.md	Updates architecture docs to remove rest-api-core references.
docs/packages.md	Removes rest-api-core references and documents SI-5 removal.
docs/issues/open/1943-1938-si-5-deprecate-rest-api-core/ISSUE.md	New folder-based issue spec with manual verification evidence.
docs/issues/open/1943-1938-si-5-deprecate-rest-api-core.md	Removes the old single-file issue spec (replaced by folder format).
docs/issues/open/1938-rest-api-contract-first-migration/EPIC.md	Updates SI-5 link to point to the folder-based issue spec.
deny.toml	Removes rest-api-core from wrapper rules.
Cargo.toml	Removes workspace dependency on torrust-tracker-rest-api-core; adds runtime-adapter entry.
Cargo.lock	Removes torrust-tracker-rest-api-core package; updates dependencies accordingly.
AGENTS.md	Updates package catalog entry from rest-api-core to rest-api-runtime-adapter.
.github/workflows/deployment.yaml	Removes cargo publish -p torrust-tracker-rest-api-core step.
.github/skills/usage/use-rest-api/SKILL.md	Adds a new skill describing how to use/verify the REST API.

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[josecelano]

ACK 5dda558