container/ps: add HealthStatus formatter field

[Mohammed-Thaha]

- What I did

Added a new docker ps --format placeholder: .HealthStatus, so users can print container health state directly as a dedicated field.

• Fixes update docs, tests, local changes for "HealthCheck" in "ps" response #6203
• relates to Add HealthStatus attribute on the docker ps command moby/moby#50281

- How I did it

• Added HealthStatus() to the container formatter context.
• Returned health directly from c.c.Health.Status when available.
• Added fallback parsing from .Status text for:
  • (healthy) -> healthy
  • (unhealthy) -> unhealthy
  • (health: starting) -> starting
• Updated docs in docs/reference/commandline/container_ls.md to include .HealthStatus in the format placeholders table.
• Added/updated unit tests in cli/command/formatter/container_test.go.

- How to verify it

1. Start dev shell:

   make -f docker.Makefile shell

2. Build the CLI binary:

   make binary

3. Run a container that stays in starting during the start period:

   docker rm -f hc-starting 2>/dev/null || true
   
   ./build/docker-linux-amd64 run -d --name hc-starting \
     --health-cmd='exit 1' \
     --health-start-period=2m \
     --health-interval=5s \
     --health-retries=1 \
     alpine sh -c 'sleep 300'

4. Verify formatter output:

   ./build/docker-linux-amd64 ps -a --filter name=hc-starting --format "table {{.Names}}\t{{.Status}}\t{{.HealthStatus}}"

Expected result:

• STATUS contains (health: starting)
• HEALTHSTATUS shows starting

- Human readable description for the release notes

`docker ps --format` now supports a `.HealthStatus` placeholder to print container health state (`starting`, `healthy`, `unhealthy`) as a dedicated field.

- A picture of a cute animal (not mandatory but encouraged)

[thaJeztah]

Thanks for working on this! I left some comments/suggestions; feedback welcome!

[thaJeztah]

Perhaps we should slightly optimise here; also adding an early return; something like;

_, health, ok := strings.Cut(c.c.Status, "(")
if !ok || !strings.HasSuffix(health, ")") {
	return ""
}


health = strings.TrimSuffix(health, ")")
health = strings.TrimPrefix(health, "health: ")

switch container.Health(health){
case container.Healthy, container.Unhealthy, container.Starting:
	return health
default:
	return ""
}

Slightly ugly because of the health: prefix but it makes it slightly more explicit that we're matching specific states.

[Mohammed-Thaha]

Used parsedHealth := container.HealthStatus(health) before the switch so the parsed value matches the container.Healthy, container.Unhealthy, and container.Starting typed constants during comparison.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 31.25000% with 11 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
cli/command/formatter/container.go	31.25%	10 Missing and 1 partial ⚠️

📢 Thoughts on this report? Let us know!

[thaJeztah]

Two minor linting issues;

75.51 cli/command/formatter/container.go:377:2: missing cases in switch of type container.HealthStatus: container.NoHealthcheck (exhaustive)
75.51 	switch parsedHealth {
75.51 	^
75.51 cli/command/formatter/container_test.go:497:1: File is not properly formatted (gofumpt)
75.51 			"HealthStatus":  "",
75.51 ^

We should also squash the commits (I may have a look later to make sure it doesn't miss the release)

[thaJeztah]

did a quick rebase and squash, and added a commit to re-format the markdown table

LGTM