feat(provider): add pipeline reasoning controls (#2373)

* feat(provider): add pipeline reasoning controls

* fix(provider): preserve local agent model compatibility

* refactor(web): use shadcn reasoning slider

* fix(runtime): stabilize reasoning chat delivery

* fix(provider): route reasoning controls by model family

* fix(provider): handle hosted Kimi reasoning protocols

* fix(provider): map qwen reasoning levels to budgets

* fix(provider): preserve think tags in streamed reasoning

* fix(provider): preserve reasoning tool metadata

* style(provider): satisfy ruff checks after merge

* fix(persistence): preserve reasoning migration compatibility

src/langbot/pkg/persistence/alembic/versions/0018_add_llm_reasoning_config.py

@@ -0,0 +1,57 @@
+"""add llm reasoning config
+
+Revision ID: 0018_llm_reasoning_config
+Revises: 0017_oss_workspace_identity
+Create Date: 2026-07-27
+"""
+
+from __future__ import annotations
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = '0018_llm_reasoning_config'
+down_revision = '0017_oss_workspace_identity'
+branch_labels = None
+depends_on = None
+
+
+_LLM_MODELS = sa.table(
+    'llm_models',
+    sa.column('reasoning_config', sa.JSON()),
+)
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+    inspector = sa.inspect(conn)
+    if 'llm_models' not in inspector.get_table_names():
+        return
+
+    columns = {column['name'] for column in inspector.get_columns('llm_models')}
+    if 'reasoning_config' in columns:
+        return
+
+    op.add_column(
+        'llm_models',
+        sa.Column(
+            'reasoning_config',
+            sa.JSON(),
+            nullable=True,
+            server_default=sa.text('\'{"level":"provider_default"}\''),
+        ),
+    )
+    conn.execute(_LLM_MODELS.update().values(reasoning_config={'level': 'provider_default'}))
+    with op.batch_alter_table('llm_models') as batch_op:
+        batch_op.alter_column('reasoning_config', existing_type=sa.JSON(), nullable=False)
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+    inspector = sa.inspect(conn)
+    if 'llm_models' not in inspector.get_table_names():
+        return
+    columns = {column['name'] for column in inspector.get_columns('llm_models')}
+    if 'reasoning_config' in columns:
+        with op.batch_alter_table('llm_models') as batch_op:
+            batch_op.drop_column('reasoning_config')

src/langbot/pkg/persistence/alembic/versions/0021_merge_reasoning_config.py

@@ -0,0 +1,21 @@
+"""merge reasoning config with the main migration branch
+
+Revision ID: 0021_merge_reasoning_config
+Revises: 0020_membership_source, 0018_llm_reasoning_config
+Create Date: 2026-08-09
+"""
+
+from __future__ import annotations
+
+revision = '0021_merge_reasoning_config'
+down_revision = ('0020_membership_source', '0018_llm_reasoning_config')
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    pass
+
+
+def downgrade() -> None:
+    pass