Replace copyrighted slide figures with freely-licensed equivalents

Three images in the methodology lecture deck lacked reuse rights:
- 41579_2024_1126_Fig1_HTML.png (© Springer Nature / Nature Reviews Microbiology)
- 340149_1_En_16_Fig6_HTML.webp (© Springer Nature / book chapter)
- burden-typhoid-vaccines.png (mapchart.net, unclear license)

Changes:
- Delete all three copyrighted files from man/figures/
- Shigella slide: remove the NRM incidence choropleth; keep the
  CDC/PHIL public-domain Shigella_stool.jpg (now with explicit CC/PD
  attribution in the caption)
- Scrub-typhus slide: remove the Springer range map; keep
  Trombicula-larva-stylostome.jpg (CC BY-SA 3.0, Alan R Walker, now
  attributed in the caption)
- Burden-data-gap slide: replace burden-typhoid-vaccines.png with an
  R code chunk that generates an equivalent TCV-adoption world map
  using map_data("world") + publicly known country list from CDC MMWR
  72(7):182–188 (public domain). Add `maps` to Config/Needs/website.
- Fix the Fievre_typhoide.png caption: it is a typhoid-distribution
  world map (CC BY-SA 3.0, Wikimedia Commons), not a "historic
  typhoid fever illustration".
- Fix the SalmonellaTyphiFlagellarStain.jpg caption to include the
  Wikimedia Commons URL.
- Remove `Springer` from inst/WORDLIST (no longer referenced).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B5FrE8RZ6EjFiz7q8zqbfg

Author: claude

DESCRIPTION

@@ -72,7 +72,7 @@ LinkingTo:
 Config/testthat/edition: 3
 Config/Needs/roxygen2: roxygen2, moodymudskipper/devtag
 Config/Needs/lint: r-lib/lintr
-Config/Needs/website: quarto, lewinfox/foodwebr, serodynamics
+Config/Needs/website: quarto, lewinfox/foodwebr, serodynamics, maps
 Config/Needs/check: readr
 Encoding: UTF-8
 Language: en-US

inst/WORDLIST

@@ -38,7 +38,6 @@ Seroepidemiology
 Seroincidence
 Serological
 Shigella
-Springer
 TCVs
 TW
 Trombicula

man/figures/340149_1_En_16_Fig6_HTML.webp

@@ -26,8 +26,8 @@ author: Ezra Morrison, Assistant Professor of Biostatistics, Department of Publi
 :::
 
 ::: {.column width="40%"}
-![*Salmonella* Typhi, flagellar stain. Source: CDC PHIL (public domain), via Wikimedia Commons.](../man/figures/SalmonellaTyphiFlagellarStain.jpg){fig-alt="Photomicrograph of *Salmonella* Typhi bacteria with a flagellar stain"}
-![Historic typhoid fever illustration. Source: Wikimedia Commons (license to verify).](../man/figures/Fievre_typhoide.png){fig-alt="Historical illustration depicting typhoid fever"}
+![*Salmonella* Typhi, flagellar stain. Photo: CDC/PHIL (public domain), via [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:SalmonellaTyphiFlagellarStain.jpg).](../man/figures/SalmonellaTyphiFlagellarStain.jpg){fig-alt="Photomicrograph of *Salmonella* Typhi bacteria with a flagellar stain"}
+![Global distribution of typhoid fever. Source: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Fievre_typhoide.png), [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/).](../man/figures/Fievre_typhoide.png){fig-alt="World map showing high (red) and moderate (orange) typhoid-burden countries"}
 
 :::
 
@@ -48,8 +48,7 @@ author: Ezra Morrison, Assistant Professor of Biostatistics, Department of Publi
 
 :::: {.column width="50%"}
 
-![*Shigella* in a stool sample. Source: Wikimedia Commons (license to verify).](../man/figures/Shigella_stool.jpg){fig-alt="Microscopy of a stool sample containing *Shigella* bacteria"}
-![From Nature Reviews Microbiology (2024). © Springer Nature — reuse permission required.](../man/figures/41579_2024_1126_Fig1_HTML.png){fig-alt="Published figure on enteric pathogen epidemiology from Nature Reviews Microbiology (2024)"}
+![*Shigella* in a stool sample. Photo: CDC/PHIL (public domain), via [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Shigella_stool.jpg).](../man/figures/Shigella_stool.jpg){fig-alt="Microscopy of a stool sample containing *Shigella* bacteria"}
 ::::
 
 :::
@@ -69,8 +68,7 @@ author: Ezra Morrison, Assistant Professor of Biostatistics, Department of Publi
 
 :::: {.column width="50%"}
 
-![*Trombicula* mite larva with stylostome. Source: Wikimedia Commons (license to verify).](../man/figures/Trombicula-larva-stylostome.jpg){fig-alt="Microscopy of a *Trombicula* mite larva with its stylostome feeding tube"}
-![From a Springer book chapter. © Springer Nature — reuse permission required.](../man/figures/340149_1_En_16_Fig6_HTML.webp){fig-alt="Published figure on scrub typhus from a Springer book chapter"}
+![*Trombicula* mite larva with stylostome. Photo: Alan R Walker / [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Trombicula-larva-stylostome.jpg), [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/).](../man/figures/Trombicula-larva-stylostome.jpg){fig-alt="Microscopy of a *Trombicula* mite larva with its stylostome feeding tube"}
 ::::
 
 :::
@@ -98,7 +96,46 @@ widening **equity gaps** in access to effective vaccines.
 
 :::: {.column width="45%"}
 
-![Global typhoid burden and the limited adoption of typhoid conjugate vaccines. Reuse permission required.](../man/figures/burden-typhoid-vaccines.png){fig-alt="Figure summarizing global typhoid burden and the limited adoption of typhoid conjugate vaccines"}
+```{r}
+#| echo: false
+#| fig-cap: >
+#|   Countries with routine TCV introduction as of 2023.
+#|   Source: CDC MMWR 72(7):182–188 (public domain).
+#| fig-alt: >
+#|   World map highlighting countries that have introduced typhoid conjugate
+#|   vaccines (TCV) into routine immunization (green). As of 2023 only a
+#|   handful of countries — Pakistan, Nepal, Liberia, Zimbabwe, Malawi, and
+#|   Samoa — have done so, despite much wider typhoid burden.
+library(ggplot2)
+
+# Countries with routine TCV introduction as of 2023
+# Source: CDC MMWR 72(7):182–188, February 17, 2023 (public domain)
+tcv_countries <- c(
+  "Pakistan", "Nepal",
+  "Liberia", "Zimbabwe", "Malawi",
+  "Samoa"
+)
+world <- map_data("world")
+world$status <- ifelse(
+  world$region %in% tcv_countries,
+  "TCV introduced", "Not yet introduced"
+)
+ggplot(world, aes(long, lat, group = group, fill = status)) +
+  geom_polygon(colour = "white", linewidth = 0.1) +
+  scale_fill_manual(
+    values = c(
+      "TCV introduced"     = "#1B9E77",
+      "Not yet introduced" = "#BBBBBB"
+    ),
+    name = NULL
+  ) +
+  coord_fixed(1.3) +
+  theme_void() +
+  theme(
+    legend.position = "bottom",
+    legend.text = element_text(size = 8)
+  )
+```
 
 ::::