docs: document POST /models/reload under model management

[pos-ei-don]

What

Adds POST /models/reload to the model-management docs, plus one missing row in the model config field table.

/models/reload is currently mentioned only in operations/middleware.md, in the context of router configs. Someone managing models reads Advanced usage → Install models using the API, finds only /models/apply — which installs from a gallery definition and downloads files — and concludes that a locally written YAML needs a restart. This puts the endpoint next to /models/apply and states the difference.

It also records a limit that is documented nowhere and is easy to get wrong: reloading adds new configurations and replaces changed ones, but does not drop a configuration whose file was deleted — that entry stays in /v1/models until restart.

The second hunk is a single row adding alias to the field table in the model configuration reference, linking to the existing Model Aliases page.

Verified

Against a running v4.7.1, not inferred from the source: adding an alias config and re-pointing an existing one both took effect after /models/reload without a restart; deleting the file did not remove the entry.

Docs only — no code changes.

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Assisted-by: Claude:claude-opus-5 — per CONTRIBUTING.md, I have reviewed the change and am responsible for it.

[localai-org-maint-bot]

The documentation matches the endpoint implementation and current additive reload behavior. The alias field and link are also accurate. The only blocker is DCO: the commit lacks a human Signed-off-by trailer, and the DCO check fails. Please amend the commit with your own sign-off and force-push it. I cannot add that attestation for you.