fix: remove YAML metadata from doc.md to fix GitHub Pages display (#405)

## Summary
- Fixes the issue where FORD configuration metadata was appearing as raw
text on GitHub Pages
- Configuration moved to fpm.toml where it belongs
- Documentation now displays cleanly without metadata artifacts

## Problem
The GitHub Pages documentation at
https://lazy-fortran.github.io/fortplot/ was showing raw YAML
configuration text instead of a clean summary. This was due to incorrect
FORD metadata format in doc.md.

## Solution
- Removed all YAML metadata from doc.md (keeping only markdown content)
- Simplified the [extra.ford] configuration in fpm.toml to essential
settings
- FORD now correctly reads configuration from fpm.toml and displays
clean documentation

## Testing
- Regenerated documentation locally with `ford doc.md`
- Verified that build/doc/index.html no longer contains metadata text
- Confirmed clean HTML output without configuration artifacts

Fixes #399

Author: krystophny

BACKLOG.md

@@ -11,10 +11,10 @@
 *All user-facing issues moved to DOING*
 
 **Infrastructure & Documentation Issues (Lower Priority)**
-- [ ] #399: Fix - Strange summary on github pages - unwanted FORD configuration appearing in documentation
 - [ ] #403: Refactor - reduce contour function complexity - functions exceed 50-line target
 
 ## DOING (Current Work)
+- [ ] #399: Fix - Strange summary on github pages - unwanted FORD configuration appearing in documentation
 
 ## FUTURE SPRINTS - Systematic Restoration
 

doc.md

@@ -1,29 +1,3 @@
-summary: Modern Fortran plotting library with multiple backends
-author: Plasma Theory Group, TU Graz
-author_description: Computational plasma physics research group
-github: https://github.com/krystophny/fortplotlib
-project_github: https://github.com/krystophny/fortplotlib
-project_download: https://github.com/krystophny/fortplotlib/releases
-output_dir: ./build/doc
-media_dir: ./doc/media
-page_dir: ./doc
-src_dir: ./src
-         ./example
-exclude_dir: ./thirdparty
-             ./build
-             ./test
-             ./app
-preprocessor: cpp -E
-macro: USE_FORD
-display: public
-         protected
-         private
-source: true
-graph: true
-search: true
-extra_mods: iso_fortran_env:https://gcc.gnu.org/onlinedocs/gfortran/ISO_005fFORTRAN_005fENV.html
-            iso_c_binding:https://gcc.gnu.org/onlinedocs/gfortran/ISO_005fC_005fBINDING.html
-
 Welcome to the fortplotlib documentation. This library provides a modern, matplotlib-inspired plotting interface for Fortran with multiple backends including PNG, PDF, and ASCII.
 
 ## Features

fpm.toml

@@ -26,7 +26,8 @@ source-form = "free"
 
 [extra.ford]
 project = "fortplot"
-src_dir = "src"
+summary = "Modern Fortran plotting library with multiple backends"
+src_dir = ["src", "example"]
 output_dir = "build/doc"
 page_dir = "doc"
 exclude = "fortplot_pdf_text.f90"