Add an opt-in lazy mode (--lazy or FORGEJO_LAZY_TOOLS=true, off by
default). The server starts with a single load_tool_area tool; calling it
enables the requested areas' tools and sends
notifications/tools/list_changed so the client reloads its tool list. The
client starts with about 600 tokens of tool definitions and instructions
instead of about 45k.

This only works with clients that reload their tool list mid-session.
Tested with Claude Code 2.1.299 over stdio and HTTP; the README and
changelog document the caveat.

The compacted tool list cache is now keyed per request on the tools the
server currently lists, so one HTTP session's loaded areas cannot leak
into another's, and it is capped at 32 entries.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BN6rD9s7tKzuxpeHJqy31q