common: fix explicit -md precedence over draft sidecar resolution (#26165)

common: fix explicit -md precedence over draft sidecar resolution (#26165)

* common: fix explicit -md precedence over draft sidecar resolution

Follow-up of #25955, an explicit --model-draft file given with -hfd
was silently overridden by the sidecar resolution of the draft repo,
and its path was never resolved to a local file.

An explicit draft file selection now disables the sidecar resolution,
so the manual CLI configuration wins over the automatic one.

* common: apply the -hfd tag to the sidecar resolution

The sidecar selection was anchored on the primary of the draft plan,
so a tag without a matching full model aborted the whole plan, and
the sidecar quant silently followed the default model pick.

The tag now anchors the sidecar directly: exact tag match first, then
closest quant to the tag, and a requested sidecar resolves even when
no full model matches the tag. A wired draft sidecar also counts as
an explicit draft, so the main plan no longer downloads a second one.

* common: promote speculative load logs from trace to info

Show the loaded draft model and the MTP draft context at the default
verbosity, for consistency with the mmproj and primary logs.

Co-authored-by: Georgi Gerganov <redacted>
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Co-authored-by: Georgi Gerganov <redacted>