feat(reports): PDF build infrastructure — premium WeasyPrint template

- report.css: full-bleed navy cover, Padelnomics logo watermark at 3.5%
  opacity (position:fixed, repeats every page), gold/teal accents, Georgia
  headings, running headers via CSS named strings, metric boxes, insight-box
- report.html: Jinja2 template with cover stats, TOC, body, disclaimer
- build_report_pdf.py: builds EN+DE PDFs from data/content/reports/*.md
  (WeasyPrint, mistune, PyYAML; reads logo as file:// URI for watermark)
- Makefile: report-pdf target

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

Makefile

@@ -2,7 +2,7 @@ TAILWIND_VERSION := v4.1.18
 TAILWIND         := ./bin/tailwindcss
 SOPS_DOTENV      := sops --input-type dotenv --output-type dotenv
 
-.PHONY: help dev init-landing-seeds css-build css-watch \
+.PHONY: help dev init-landing-seeds css-build css-watch report-pdf \
         secrets-decrypt-dev secrets-decrypt-prod \
         secrets-edit-dev secrets-edit-prod \
         secrets-encrypt-dev secrets-encrypt-prod
@@ -13,6 +13,7 @@ help:
 	@echo "  init-landing-seeds     Create seed landing files for SQLMesh (run once after clone)"
 	@echo "  css-build              Build + minify Tailwind CSS"
 	@echo "  css-watch              Watch + rebuild Tailwind CSS"
+	@echo "  report-pdf             Build market intelligence report PDFs (WeasyPrint)"
 	@echo "  secrets-decrypt-dev    Decrypt .env.dev.sops → .env"
 	@echo "  secrets-decrypt-prod   Decrypt .env.prod.sops → .env"
 	@echo "  secrets-edit-dev       Edit .env.dev.sops in \$$EDITOR"
@@ -45,6 +46,9 @@ css-build: bin/tailwindcss
 css-watch: bin/tailwindcss
 	$(TAILWIND) -i web/src/padelnomics/static/css/input.css -o web/src/padelnomics/static/css/output.css --watch
 
+report-pdf:
+	uv run python web/scripts/build_report_pdf.py
+
 # ── Secrets (SOPS + age) ─────────────────────────────────────────────────────
 # Requires: sops (https://github.com/getsops/sops) + age (https://github.com/FiloSottile/age)
 # Keys config: .sops.yaml