0.2.27-0.2.32: LP portal polish, brand palette, default investor logins

Cumulative checkpoint since 0.2.26:
- 0.2.27/28: entity valuation-history table; investor gain/loss = NAV +
  distributions vs paid-in
- 0.2.29: Reset Fund Partners (endpoint, Partners-tab button, CLI, action)
- 0.2.30: "Current Capital Balance" label, %-only gain/loss
- 0.2.31: Management Entities rename, Carry Vehicle type, chart
  distributions-line gate
- 0.2.32: LP-facing polish pass
  * Ten31 brand palette from the logo (navy/mint); orange retired
  * portfolio summary card across funds; gain labeled "net of paid-in"
  * whole-dollar headline figures; "History · N quarters" toggle
  * documents grouped by year with a "New" badge (users.docs_seen_at)
  * eNAV-created members start on default password with login enabled;
    enable-investor-logins CLI + StartOS action for existing accounts
  * password minimum raised to 8 chars; login help line (Portal@ten31.xyz)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/alembic/versions/d0e1f2a3b4c5_docs_seen_at.py

@@ -0,0 +1,27 @@
+"""add users.docs_seen_at (portal "New" document badge watermark)
+
+Revision ID: d0e1f2a3b4c5
+Revises: c9d0e1f2a3b4
+Create Date: 2026-07-03 09:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision: str = 'd0e1f2a3b4c5'
+down_revision: Union[str, None] = 'c9d0e1f2a3b4'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    with op.batch_alter_table('users', schema=None) as batch_op:
+        batch_op.add_column(sa.Column('docs_seen_at', sa.DateTime(), nullable=True))
+
+
+def downgrade() -> None:
+    with op.batch_alter_table('users', schema=None) as batch_op:
+        batch_op.drop_column('docs_seen_at')