feat(coord): add todos system with per-user/machine/project scoping

New coord_todos table and API endpoints (GET/POST/PUT/DELETE /api/coord/todos)
supporting manual and auto-created items, sub-tasks via parent_id, and inclusive
for_user/for_machine filters (OR-null) for sync/save display. sync.sh Phase 7
now shows pending todos grouped by project after every sync. CLAUDE.md documents
auto-creation behavior for unresolved follow-up. Web/email pricing doc updated:
block time rate clarified, INKY reference removed, dates updated.

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

migrations/versions/20260526_120000_coord_todos.py

@@ -0,0 +1,53 @@
+"""coord_todos
+
+Revision ID: 20260526_120000
+Revises: 20260512_120000
+Create Date: 2026-05-26 12:00:00
+
+Creates the coord_todos table for personal and project-scoped to-do items,
+supporting sub-tasks via a self-referencing parent_id FK.
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "20260526_120000"
+down_revision: Union[str, None] = "20260512_120000"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Create coord_todos table."""
+    op.create_table(
+        "coord_todos",
+        sa.Column("id", sa.CHAR(36), primary_key=True),
+        sa.Column("text", sa.Text(), nullable=False),
+        sa.Column("project_key", sa.String(100), nullable=True),
+        sa.Column("parent_id", sa.CHAR(36), sa.ForeignKey("coord_todos.id", ondelete="CASCADE"), nullable=True),
+        sa.Column("assigned_to_user", sa.String(50), nullable=True),
+        sa.Column("assigned_to_machine", sa.String(100), nullable=True),
+        sa.Column("auto_created", sa.Boolean(), nullable=False, server_default=sa.text("0")),
+        sa.Column("source_context", sa.Text(), nullable=True),
+        sa.Column("status", sa.String(20), nullable=False, server_default="pending"),
+        sa.Column("completed_at", sa.DateTime(), nullable=True),
+        sa.Column("completed_by", sa.String(100), nullable=True),
+        sa.Column("created_by_user", sa.String(50), nullable=False),
+        sa.Column("created_by_machine", sa.String(100), nullable=False),
+        sa.Column("created_at", sa.DateTime(), nullable=False, server_default=sa.text("CURRENT_TIMESTAMP")),
+        sa.Column("updated_at", sa.DateTime(), nullable=False, server_default=sa.text("CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP")),
+        sa.CheckConstraint(
+            "status IN ('pending', 'done', 'cancelled')",
+            name="ck_coord_todos_status",
+        ),
+    )
+    op.create_index("idx_coord_todos_project_status", "coord_todos", ["project_key", "status"])
+    op.create_index("idx_coord_todos_assigned", "coord_todos", ["assigned_to_user", "assigned_to_machine", "status"])
+    op.create_index("idx_coord_todos_parent", "coord_todos", ["parent_id"])
+
+
+def downgrade() -> None:
+    """Drop coord_todos table."""
+    op.drop_table("coord_todos")