feat(knowledge-flywheel): add Phase 3 Knowledge Flywheel — AI analysis, review queue, analytics

Phase 3 implementation:
- AI session analysis service that generates flow proposals from resolved sessions
- APScheduler job for batch processing pending analyses (max_instances=1)
- Knowledge gap detection (weak options, high escalation signals)
- Flow proposals CRUD with team admin review workflow (approve/edit/dismiss/reject)
- FlowPilot analytics dashboard with confidence tiers, PSA metrics, knowledge gaps
- In-session script generator component
- Review queue page with filtering and proposal detail panel

Bug fixes from review (12 total):
- Fix "Edit & Publish" navigating to non-existent /editor/new route
- Hide Approve button for enhancement proposals (require Edit & Publish)
- Add max_instances=1 to scheduler to prevent TOCTOU race
- Fix eventual_success case() double-counting failed retries
- Add tree_structure validation before creating tree from proposal
- Simplify script generator rendering condition
- Add severity style fallback, toFixed on rates, Link instead of <a href>
- Add toast.warning on dismiss failure, fix dedup for domain-less sessions
- Cast Decimal to int in knowledge gap evidence dicts

Also updates CLAUDE.md with lessons 67-71 and Phase 3 project structure.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/alembic/versions/3266dd9d8111_add_ai_session_id_to_script_generations.py

@@ -0,0 +1,40 @@
+"""add ai_session_id to script_generations
+
+Revision ID: 3266dd9d8111
+Revises: a0b871cb0c5e
+Create Date: 2026-03-19 03:52:09.457961
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = '3266dd9d8111'
+down_revision: Union[str, None] = 'a0b871cb0c5e'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column('script_generations', sa.Column(
+        'ai_session_id', sa.UUID(), nullable=True,
+        comment='FlowPilot AI session that triggered this generation',
+    ))
+    op.create_index(
+        op.f('ix_script_generations_ai_session_id'),
+        'script_generations', ['ai_session_id'], unique=False,
+    )
+    op.create_foreign_key(
+        'fk_script_generations_ai_session_id',
+        'script_generations', 'ai_sessions',
+        ['ai_session_id'], ['id'],
+        ondelete='SET NULL',
+    )
+
+
+def downgrade() -> None:
+    op.drop_constraint('fk_script_generations_ai_session_id', 'script_generations', type_='foreignkey')
+    op.drop_index(op.f('ix_script_generations_ai_session_id'), table_name='script_generations')
+    op.drop_column('script_generations', 'ai_session_id')

backend/alembic/versions/47c3b4f42e88_add_flow_proposals_table.py

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+"""add flow_proposals table
+
+Revision ID: 47c3b4f42e88
+Revises: cc3201489b72
+Create Date: 2026-03-19 03:11:33.663729
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = '47c3b4f42e88'
+down_revision: Union[str, None] = 'cc3201489b72'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table('flow_proposals',
+        sa.Column('id', sa.UUID(), nullable=False),
+        sa.Column('account_id', sa.UUID(), nullable=False),
+        sa.Column('team_id', sa.UUID(), nullable=True),
+        sa.Column('source_session_id', sa.UUID(), nullable=False),
+        sa.Column('proposal_type', sa.String(length=30), nullable=False),
+        sa.Column('target_flow_id', sa.UUID(), nullable=True, comment='For enhancements: which existing flow to modify'),
+        sa.Column('title', sa.String(length=255), nullable=False, comment='Human-readable title for the proposed flow'),
+        sa.Column('description', sa.Text(), nullable=True, comment='AI-generated description of what this flow covers'),
+        sa.Column('proposed_flow_data', postgresql.JSONB(astext_type=sa.Text()), nullable=False, comment='Complete flow/tree_structure definition (nodes, edges, conditions)'),
+        sa.Column('proposed_diff', postgresql.JSONB(astext_type=sa.Text()), nullable=True, comment='For enhancements: what changed vs existing flow'),
+        sa.Column('confidence_score', sa.Float(), nullable=False, comment='How confident the system is in this proposal (0.0-1.0)'),
+        sa.Column('supporting_session_count', sa.Integer(), nullable=False, comment='Number of sessions with similar resolution paths'),
+        sa.Column('supporting_session_ids', postgresql.JSONB(astext_type=sa.Text()), nullable=False, comment='Array of session IDs that support this proposal'),
+        sa.Column('problem_domain', sa.String(length=100), nullable=True),
+        sa.Column('status', sa.String(length=30), nullable=False),
+        sa.Column('reviewed_by', sa.UUID(), nullable=True),
+        sa.Column('reviewer_notes', sa.Text(), nullable=True),
+        sa.Column('published_flow_id', sa.UUID(), nullable=True, comment='The flow that was created/updated when this proposal was approved'),
+        sa.Column('created_at', sa.DateTime(timezone=True), nullable=False),
+        sa.Column('reviewed_at', sa.DateTime(timezone=True), nullable=True),
+        sa.CheckConstraint("proposal_type IN ('new_flow', 'enhancement', 'branch_addition', 'auto_reinforced')", name='ck_flow_proposals_type'),
+        sa.CheckConstraint("status IN ('pending', 'approved', 'modified', 'rejected', 'dismissed', 'auto_reinforced')", name='ck_flow_proposals_status'),
+        sa.ForeignKeyConstraint(['account_id'], ['accounts.id'], ondelete='CASCADE'),
+        sa.ForeignKeyConstraint(['published_flow_id'], ['trees.id'], ondelete='SET NULL'),
+        sa.ForeignKeyConstraint(['reviewed_by'], ['users.id'], ondelete='SET NULL'),
+        sa.ForeignKeyConstraint(['source_session_id'], ['ai_sessions.id'], ondelete='CASCADE'),
+        sa.ForeignKeyConstraint(['target_flow_id'], ['trees.id'], ondelete='SET NULL'),
+        sa.ForeignKeyConstraint(['team_id'], ['teams.id'], ondelete='SET NULL'),
+        sa.PrimaryKeyConstraint('id'),
+    )
+    op.create_index(op.f('ix_flow_proposals_account_id'), 'flow_proposals', ['account_id'], unique=False)
+    op.create_index(op.f('ix_flow_proposals_source_session_id'), 'flow_proposals', ['source_session_id'], unique=False)
+    op.create_index(op.f('ix_flow_proposals_status'), 'flow_proposals', ['status'], unique=False)
+    op.create_index(op.f('ix_flow_proposals_team_id'), 'flow_proposals', ['team_id'], unique=False)
+
+
+def downgrade() -> None:
+    op.drop_index(op.f('ix_flow_proposals_team_id'), table_name='flow_proposals')
+    op.drop_index(op.f('ix_flow_proposals_status'), table_name='flow_proposals')
+    op.drop_index(op.f('ix_flow_proposals_source_session_id'), table_name='flow_proposals')
+    op.drop_index(op.f('ix_flow_proposals_account_id'), table_name='flow_proposals')
+    op.drop_table('flow_proposals')

backend/alembic/versions/a0b871cb0c5e_add_analysis_status_to_ai_sessions.py

@@ -0,0 +1,28 @@
+"""add analysis_status to ai_sessions
+
+Revision ID: a0b871cb0c5e
+Revises: 47c3b4f42e88
+Create Date: 2026-03-19 03:26:26.965134
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = 'a0b871cb0c5e'
+down_revision: Union[str, None] = '47c3b4f42e88'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column('ai_sessions', sa.Column(
+        'analysis_status', sa.String(length=20), nullable=True,
+        comment='Knowledge Flywheel status: null (N/A), pending, completed, failed',
+    ))
+
+
+def downgrade() -> None:
+    op.drop_column('ai_sessions', 'analysis_status')