Library AllRefs implies tag inclusion; close the contract gap

The library docs and the unstable fetch CLI promised "every refs/*", but BuildDesiredRefs and addPruneCandidates excluded tags unless IncludeTags was set. The CLI sync/bootstrap wrappers papered over this by implying --tags, but library callers and fetch --all-refs got a narrower scope than the wording promised.

Move the tag-inclusion implication into the library so the contract is honest at every layer:

• BuildDesiredRefs adds source tags when IncludeTags || AllRefs.
• addPruneCandidates' tag-prune case fires under the same condition.
• replicateCanBootstrap matches.

Drop the now-redundant CLI bundling: sync/bootstrap no longer set IncludeTags from --all-refs because the library covers it. SyncPolicy. BestEffort stays orthogonal so callers can opt into per-ref warn semantics on a narrower scope.

Updated the planner test that asserted the old (wrong) "tag should not appear without IncludeTags" behavior, and added a fetch CLI smoke test verifying fetch --all-refs puts tag and notes refs into the wants list without --tags being passed.