feat: add procedural flows with intake forms, navigation, and seed templates

Adds a new "procedural" tree type for linear step-by-step project workflows
(domain controller setup, M365 onboarding, VPN config, etc). Includes intake
form builder, two-panel step navigation, variable resolution, procedural
exports, 3 seed templates, and UI rename from "Trees" to "Flows".

Also archives 19 implemented plan docs and creates deferred features backlog.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/alembic/versions/035_add_tree_type_and_intake_form.py

@@ -0,0 +1,47 @@
+"""add tree_type and intake_form to trees
+
+Revision ID: 035
+Revises: 034
+Create Date: 2026-02-14
+
+Adds tree_type (troubleshooting/procedural) and intake_form (JSONB) columns to trees table.
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import JSONB
+
+
+# revision identifiers, used by Alembic.
+revision: str = '035'
+down_revision: Union[str, None] = '034'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column('trees', sa.Column(
+        'tree_type',
+        sa.String(20),
+        nullable=False,
+        server_default='troubleshooting',
+    ))
+    op.add_column('trees', sa.Column(
+        'intake_form',
+        JSONB(),
+        nullable=True,
+    ))
+    op.create_check_constraint(
+        'ck_trees_tree_type',
+        'trees',
+        "tree_type IN ('troubleshooting', 'procedural')",
+    )
+    op.create_index('ix_trees_tree_type', 'trees', ['tree_type'])
+
+
+def downgrade() -> None:
+    op.drop_index('ix_trees_tree_type', table_name='trees')
+    op.drop_constraint('ck_trees_tree_type', 'trees', type_='check')
+    op.drop_column('trees', 'intake_form')
+    op.drop_column('trees', 'tree_type')