chore: fix packaging metadata, dependency alerts and Docker tag guidance

[marevol]

Summary

Three follow-ups noticed while cutting the 0.3.0 release. No runtime code changes.

1. typer[all] is not a real extra

typer 0.16.0 publishes no all extra, so every install prints:

warning: The package `typer==0.16.0` does not have an extra named `all`

Relocking after removing it changes no resolved package, which confirms the extra
was already a no-op — plain typer pulls click, rich, shellingham and
typing-extensions on its own.

2. Dependency alerts

All nine open Dependabot alerts are transitive packages in uv.lock. Upgraded with
targeted uv lock --upgrade-package so the pinned direct dependencies
(httpx==0.28.1, pyyaml==6.0.2, typer==0.16.0) stay exactly as they are:

package	before	after	patched at
urllib3	2.5.0	2.7.0	2.7.0 (4 alerts, high)
idna	3.11	3.19	3.15
requests	2.32.5	2.34.2	2.33.0
pytest	9.0.1	9.1.1	9.0.3
python-dotenv	1.2.1	1.2.3	1.2.2
pygments	2.19.2	2.21.0	2.20.0

3. Docker tag guidance in the skill docs was wrong

Image tags on ghcr.io/codelibs/fessctl are fessctl release versions (0.1.0,
0.2.0, 0.3.0, plus snapshot). The docs described them as tracking the Fess
version, which is selected at runtime by FESS_VERSION and has nothing to do with the
tag. The install skill's runner detection therefore built an image reference that can
never resolve:

ghcr.io/codelibs/fessctl:${FESS_VERSION:-latest}   # -> ...:15.8.0, which does not exist

There is also no latest tag on this image, so the fallback was equally broken and the
troubleshooting page recommended it too. Fixed in references/installation.md (runner
detection now pins 0.3.0; the "Choosing the Docker tag" section states what tags mean)
and references/troubleshooting.md (a missing tag fails with manifest unknown, not
denied, so both error strings are now covered).

Verification

• uv run pytest tests/unit — 123 passed with the upgraded lockfile
• docker pull ghcr.io/codelibs/fessctl — manifest unknown (confirms no latest tag)
• docker run ... ghcr.io/codelibs/fessctl:0.3.0 — reports package version 0.3.0,
  default FESS_VERSION 15.8.0