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/ten31portal/schemas.py

@@ -212,6 +212,8 @@ class DocumentResponse(BaseModel):
     size_bytes: int
     uploaded_by: int | None
     created_at: datetime
+    # True for an investor when the doc arrived since their previous portal visit.
+    is_new: bool = False
 
 
 # --- Capital account ---
@@ -310,7 +312,7 @@ class ImportCommitInvestor(BaseModel):
     name: str | None = None           # for action=create
     username: str | None = None       # for action=create
     email: str | None = None
-    password: str | None = None       # for action=create; omit to create without a login
+    password: str | None = None       # for action=create; omit for the shared default password
     external_id: str | None = None    # fund-admin INVESTOR ID, stored for re-import matching