Add legacy MCP tools for recent and saved food collections

[tomerh2001]

Summary

• add MCP tools for recent foods, frequent foods, and My Foods
• fetch those collections through the legacy diary-add AJAX endpoints with fresh CSRF headers
• document the newer-route logout failure mode and the supported workaround in the README

Why

Newer account routes such as /food/mine, /meal/mine, and /food/new can redirect to /account/logout in this environment even while diary reads and authenticated API token fetches still work. That made simple account-level food list requests slow and brittle to answer manually.

This change gives the MCP first-class tools for those queries and documents the non-obvious legacy path that still behaves reliably.

Notes

I attempted to create a tracking issue in the fork first to follow the normal fork flow, but GitHub Issues are disabled on this repository, so there was no issue to link.

Verification

• python -m py_compile src/mfp_mcp/server.py
• exercised mfp_get_recent_foods, mfp_get_frequent_foods, and mfp_get_my_foods locally against a live authenticated session
• confirmed the new tools returned expected counts and sample items from the account

[AdamWalt]

~1,000 lines of new logic covering HTML parsing, write operations, and entry ID matching with no tests. The PR description mentions manual verification against a live session, which is great for smoke testing, but I'd like to see at least unit tests for the pure functions before merging:

• normalize_food_collection_item — various shapes of the legacy JSON payload
• resolve_weight_id — matching by label, falling back to selected/first option
• find_replacement_entry — the progressive fallback logic (meal match, short_name match, name match, singleton)
• meal_name_to_id / meal_id_to_name — edge cases like "snack" vs "snacks"

These don't need a live MFP session and would catch regressions if MFP changes their HTML structure.

[AdamWalt]

Thanks for the contribution — the code quality here is solid. The entry_id extraction, legacy AJAX endpoint discovery, and the replacement-entry matching logic are useful additions.

A few things I'd like addressed before approving:

1. Blocker: Thread safety of the create_mfp_client monkey-patch (see comment)
2. Requested: Unit tests for the pure helper functions (see comment)

Happy to re-review once those are addressed.