Replace hand-rolled base64 dicts with FastMCP's Image() helper in
get_imagery, compare_dates, get_imagery_composite, and get_legend.
FastMCP handles base64 encoding and MIME type automatically.
Add Context progress reporting to imagery tools so MCP clients can
display fetch status (resolving location, fetching imagery, etc).
Add dynamic resources:
gibs://colormap/{layer_id} — colormap explanation text
gibs://dates/{layer_id} — date range + live DescribeDomains
Remove unused base64 import.
Ryan Malloy
db6ed2f550