Generate the codebase metrics page from a committed script

The codebase metrics page (docs/metrics.md) has been maintained by hand, so its numbers and its inline SVG charts drift from the code between refreshes. This adds a committed generator that produces the whole page from measured data, and regenerates the page from it.

What this does

• Adds scripts/generate-metrics.php: it reads the per-file JSON from cloc on stdin and writes docs/metrics.md (prose, tables and inline SVG charts) from a set of documented counting rules. Every number and bar is derived; nothing on the page is hand-maintained.
• Regenerates docs/metrics.md from the current 1.x. The per-submodule breakdown now sums exactly to the totals (the hand-made page left a small unattributed remainder), services count service definitions only (aliases excluded), and plugins are counted by class.

Security

The committed script executes no commands (no shell_exec, exec, system, passthru, proc_open, popen or eval), refuses to run outside the CLI, does all file discovery with native PHP filesystem APIs, and only reads files plus writes the single docs/metrics.md. You run cloc yourself and pipe its JSON in; the script never invokes it.

Usage

From the module root:

cloc --exclude-dir=node_modules --by-file --json --quiet . | php scripts/generate-metrics.php