Add print view, board info card and document logo upload

- Seitenansicht (/projects/:projectId/print): tabular cover page, board
  overview with supply structure and power sums, one plan per board with a
  repeating title block; PDF via the browser print dialog with named @page
  rules (A4 portrait cover, A4/A3 landscape plans, page x of y).
- Distribution-board info card (board number, location, fed-from, remark)
  in the board edit dialog, persisted through the additively extended
  distribution-board.update command (migration 0008, snapshot schema 6,
  legacy subtree commands normalized).
- Global document logo upload (PNG/JPEG/SVG, max 2 MB) outside project
  revisions and snapshots.
- fed-from stays free text; the overview hierarchy and cumulated sums are
  preliminary until the feed link is modeled.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/db/migrations/0007_board_info_and_document_logo.sql

@@ -0,0 +1,12 @@
+CREATE TABLE `document_branding_assets` (
+	`key` text PRIMARY KEY NOT NULL,
+	`mime_type` text NOT NULL,
+	`file_name` text,
+	`data` blob NOT NULL,
+	`updated_at` integer DEFAULT (unixepoch()) NOT NULL
+);
+--> statement-breakpoint
+ALTER TABLE `distribution_boards` ADD `board_number` text;--> statement-breakpoint
+ALTER TABLE `distribution_boards` ADD `location` text;--> statement-breakpoint
+ALTER TABLE `distribution_boards` ADD `fed_from` text;--> statement-breakpoint
+ALTER TABLE `distribution_boards` ADD `remark` text;