feat(suggestions): overlay CCIP character matches onto the rail (#114)

SuggestionService.for_image now merges CCIP character matches with the SigLIP
head suggestions — they're complementary, not exclusive: CCIP is the identity-
specialized signal but needs a detected figure; the heads work whole-image but
conflate identity with style. Merged by tag: 'both' when they corroborate
(higher score wins), 'ccip' / 'head' otherwise. Cheap when no CCIP vectors exist
yet (match_image returns early without a figure vector), so it's a no-op until
the agent runs. Suggestion.source is now 'head' | 'ccip' | 'both'.

Test: a character with a CCIP reference figure surfaces (source='ccip') on a new
image whose figure matches.

NEXT: the agent container (real CCIP/detector models, hands-on) that produces the
vectors this consumes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ttrj5P7upUTueSfoJcxEqa

backend/app/services/ml/suggestions.py

@@ -16,6 +16,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from ...models import ImageRecord, TagSuggestionRejection
 from ...models.tag import image_tag
+from .ccip import match_image as ccip_match_image
 from .heads import score_image
 
 
@@ -27,7 +28,7 @@ class Suggestion:
     display_name: str
     category: str
     score: float
-    source: str  # 'head' (Camie 'tagger'/'centroid' sources removed in v2)
+    source: str  # 'head' | 'ccip' | 'both' (Camie tagger/centroid removed in v2)
     creates_new_tag: bool
     # raw_name = the booru model vocab key behind this suggestion. It's the key
     # an alias MUST be stored under (resolution looks up the raw key), so the
@@ -92,19 +93,39 @@ class SuggestionService:
         hits = await score_image(
             self.session, image_id, threshold_override=threshold_override
         )
+        # CCIP character matches OVERLAY the SigLIP character heads — a
+        # complementary, identity-specialized signal with different failure modes
+        # (CCIP needs a detected figure; heads work whole-image). Merged by tag:
+        # 'both' when they corroborate, taking the higher score.
+        ccip_hits = await ccip_match_image(self.session, image_id)
+
+        merged: dict[tuple[str, int], dict] = {}
+        for h in hits:
+            merged[(h["category"], h["tag_id"])] = {
+                "name": h["name"], "score": h["score"], "source": "head",
+            }
+        for c in ccip_hits:
+            key = ("character", c["tag_id"])
+            ex = merged.get(key)
+            if ex is not None:
+                ex["source"] = "both"
+                ex["score"] = max(ex["score"], c["score"])
+            else:
+                merged[key] = {
+                    "name": c["name"], "score": c["score"], "source": "ccip",
+                }
 
         result = SuggestionList()
-        for h in hits:
-            tag_id = h["tag_id"]
+        for (cat, tag_id), m in merged.items():
             if tag_id in applied:
                 continue
-            result.by_category.setdefault(h["category"], []).append(
+            result.by_category.setdefault(cat, []).append(
                 Suggestion(
                     canonical_tag_id=tag_id,
-                    display_name=h["name"],
-                    category=h["category"],
-                    score=h["score"],
-                    source="head",
+                    display_name=m["name"],
+                    category=cat,
+                    score=m["score"],
+                    source=m["source"],
                     creates_new_tag=False,
                     rejected=tag_id in rejected,
                 )

tests/test_ml_suggestions.py

@@ -4,7 +4,7 @@ scikit-learn, ml image only); scoring is numpy-only (available via pgvector)."""
 import pytest
 from sqlalchemy import select
 
-from backend.app.models import ImageRecord, MLSettings, TagHead, TagKind
+from backend.app.models import ImageRecord, ImageRegion, MLSettings, TagHead, TagKind
 from backend.app.models.tag import image_tag
 from backend.app.services.ml.allowlist import AllowlistService
 from backend.app.services.ml.suggestions import SuggestionService
@@ -131,3 +131,35 @@ async def test_rejected_tag_surfaced_flagged_then_reversible(db):
     sl2 = await SuggestionService(db).for_image(img.id)
     s2 = next(x for x in sl2.by_category["general"] if x.canonical_tag_id == tag.id)
     assert s2.rejected is False
+
+
+async def _figure(db, image_id, slot):
+    v = [0.0] * 768
+    v[slot] = 1.0
+    db.add(ImageRegion(
+        image_record_id=image_id, kind="figure",
+        rx=0.0, ry=0.0, rw=1.0, rh=1.0,
+        ccip_embedding=v, embedding_version="ccip-test",
+    ))
+
+
+@pytest.mark.asyncio
+async def test_ccip_character_surfaces_in_rail(db):
+    # A character with a CCIP reference (a tagged figure) is suggested on a new
+    # image whose figure matches — overlaid into the rail alongside the heads.
+    raven = await TagService(db).find_or_create("Raven", TagKind.character)
+    ref = await _img(db, "0" * 64, None)         # the operator's tagged example
+    await _figure(db, ref.id, slot=0)
+    await db.execute(image_tag.insert().values(
+        image_record_id=ref.id, tag_id=raven.id, source="manual",
+    ))
+    query = await _img(db, "1" * 64, None)        # untagged, matching figure
+    await _figure(db, query.id, slot=0)
+    await db.commit()
+
+    sl = await SuggestionService(db).for_image(query.id)
+    m = next(
+        c for c in sl.by_category.get("character", [])
+        if c.canonical_tag_id == raven.id
+    )
+    assert m.source == "ccip"