Update default Deno and PostgreSQL versions

[myty]

Updates default Deno version from 2.0.0 to 2.4.3 and PostgreSQL version from 16 to 17 across devcontainer templates. Also modernizes Deno imports to use JSR imports and adds improved project structure with testing capabilities.

• Updates Deno version to 2.4.3 and PostgreSQL to version 17 in template configurations
• Modernizes Deno imports from URL-based to JSR-based imports (@std/assert, @db/postgres)
• Adds project configuration files and testing infrastructure

[Copilot]

Pull Request Overview

This PR updates the default versions for Deno (from 2.0.0 to 2.4.3) and PostgreSQL (from 16 to 17) across devcontainer templates while modernizing the Deno import system to use JSR-based imports instead of URL-based imports.

• Updates Deno to version 2.4.3 and PostgreSQL to version 17 as new defaults
• Modernizes Deno imports from URL-based to JSR imports (@std/assert, @db/postgres)
• Adds project configuration and testing infrastructure improvements

Reviewed Changes

Copilot reviewed 16 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test/deno/main_test.ts	Updates import to use JSR-based @std/assert
test/deno/main.ts	Adds main execution block for direct script running
test/deno/deno.json	Adds import map configuration for JSR dependencies
test/deno-postgres/main_test.ts	Updates PostgreSQL import to JSR-based @db/postgres
test/deno-postgres/deno.json	Adds import map for PostgreSQL JSR dependency
src/deno/devcontainer-template.json	Updates default Deno version to 2.4.3
src/deno/README.md	Updates documentation to reflect new Deno version
src/deno-postgres/devcontainer-template.json	Updates default versions for both Deno and PostgreSQL
src/deno-postgres/README.md	Updates documentation for new version defaults
package.json	Adds test script configuration
README.md	Improves documentation with getting started section
.github/workflows/test-pr.yaml	Updates GitHub Actions versions and filter patterns
.github/workflows/release.yaml	Updates checkout action and adds permissions
.github/actions/smoke-test/build.sh	Improves test utilities copying
.github/actions/smoke-test/action.yml	Updates checkout action version
.dev/runner.sh	Adds test runner script for local development

Comments suppressed due to low confidence (4)

.github/workflows/test-pr.yaml:11

• The dorny/paths-filter action is being downgraded from v3 to v2. Since this PR is from August 2025 and v3 was already in use, this appears to be a downgrade to an older version which may not include recent fixes or features.

      - uses: dorny/paths-filter@v2

.github/workflows/test-pr.yaml:27

• The actions/checkout action is being downgraded from v4 to v3. This is a downgrade to an older version that may lack security updates and performance improvements available in v4.

      - uses: actions/checkout@v3

.github/workflows/release.yaml:14

• The actions/checkout action is being downgraded from v4 to v3. This downgrade may introduce security vulnerabilities and remove performance improvements.

      - uses: actions/checkout@v3

.github/actions/smoke-test/action.yml:12

• The actions/checkout action is being downgraded from v4 to v3, which may introduce security and performance regressions.

      uses: actions/checkout@v3