fix(links): let CivitAI and HuggingFace links coexist (#1094)

A model could have CivitAI metadata and a HuggingFace link at the same time,
but only one of the two "View on ..." entries ever rendered, because both the
model modal and the card globe asked the `from_civitai` provenance flag which
source to show. `set_hf_url` wrote `false` and a CivitAI refresh wrote `true`,
so whichever ran last erased the other: linking HF hid "View on CivitAI" even
though the civitai payload was still in the sidecar, and (on the card) a later
refresh pointed the single globe icon back at CivitAI, hiding the HF entry.

Decide the links from the data itself instead:

- `set_hf_url` no longer touches `from_civitai`; it records where the metadata
  came from, and HF provenance is already tracked by `hf_url`.
- Add `hasCivitaiSource(civitai)` in the shared card/modal utils and gate the
  modal's CivitAI link, the card globe (title, enabled state, click target,
  new `data-has_civitai`) and the context-menu `civitai` action on actual
  CivitAI data (`modelId` / `model_id` / `id`). A dual-source model now shows
  both links, and a CivitAI-only model with no `hf_url` stays as before.
- Agent HF enrichment (`PostProcessor.is_hf_model`) keyed off
  `not from_civitai`, which stopped being a synonym for "has an HF source" once
  both sources can coexist (and already broke after a CivitAI refresh flipped
  the flag back to true). Key it off `hf_url` directly; the post-processor
  tests move to that discriminator and gain a dual-source case.

Regression tests: the set-hf-url handler preserves civitai + `from_civitai`
and no longer forces the flag false, the modal renders both links (including
with `from_civitai: false`), and the card globe targets/opens the right source
and is disabled when neither is available.

Backend: 2749 passed. Frontend: 1098 JS + 91 Vue tests passed.

py/routes/handlers/hf_handlers.py

@@ -240,7 +240,10 @@ class HfHandler:
                 })
 
             existing["hf_url"] = hf_url
-            existing["from_civitai"] = False
+            # NOTE: deliberately do NOT touch `from_civitai` here. It records
+            # where the metadata came from, and the UI must show the CivitAI
+            # link whenever CivitAI data is present — linking HuggingFace must
+            # not hide it (#1094). HF provenance is tracked via `hf_url`.
             await MetadataManager.save_metadata(file_path, existing)
 
             await _add_to_scanner_cache(file_path, existing)