Feat/rerank model (#2137)

* feat(provider): add rerank model management as a core model type

* feat(provider): add rerank support to existing requesters and new rerank providers

* feat(web): add rerank model management UI and pipeline config

* fix(provider): correct rerank support_type after verification

- Add rerank to OpenRouter (confirmed /api/v1/rerank endpoint)
- Remove rerank from Ollama (no native support, PR #7219 unmerged)
- Remove rerank from JiekouAI (no rerank docs found, URL path mismatch)

* fix(provider): remove alru_cache from model getters and add rerank param hints

* fix: resolve lint errors

- Remove unused alru_cache import from modelmgr.py
- Remove unused error_message variable in invoke_rerank
- Fix prettier formatting in frontend files

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* fix: remove unused exception variable

- Change `except Exception as e:` to `except Exception:` since e is not used
- Fix prettier formatting in ProviderCard.tsx

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* fix: apply ruff format

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* feat(template): add rerank config fields to default pipeline config

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* chore: remove PR.md

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* fix(ui): remove duplicate rerank model form in AddModelPopover

The form was being rendered twice: once in TabsContent manual mode
and again in a separate conditional block for rerank tab.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

src/langbot/pkg/persistence/alembic/versions/0003_add_rerank_models.py

@@ -0,0 +1,31 @@
+"""add rerank_models table
+
+Revision ID: 0003_add_rerank_models
+Revises: 0002_sample
+Create Date: 2026-04-19
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = '0003_add_rerank_models'
+down_revision = '0002_sample'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        'rerank_models',
+        sa.Column('uuid', sa.String(255), primary_key=True, unique=True),
+        sa.Column('name', sa.String(255), nullable=False),
+        sa.Column('provider_uuid', sa.String(255), nullable=False),
+        sa.Column('extra_args', sa.JSON, nullable=False, server_default='{}'),
+        sa.Column('prefered_ranking', sa.Integer, nullable=False, server_default='0'),
+        sa.Column('created_at', sa.DateTime, nullable=False, server_default=sa.func.now()),
+        sa.Column('updated_at', sa.DateTime, nullable=False, server_default=sa.func.now()),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table('rerank_models')