Answers spec v1.4: param_bounds + upcoming calendars fetch from today forward

[SecureCloudGroup]

Round 20, Q3b (the app's query layer) needs two Library changes.

• param_bounds (answers spec v1.4, optional, closed): on a list/columns answer, {<cell path>: {min?: <param>, max?: <param>}} names the address parameter that bounds a number cell from below or above, so the app can push an asked comparator into the address ("earthquakes above magnitude 4" fetches with minmagnitude=4 instead of the default 2.5) while the card's own row filter stays. Validation in answers.py (the cell is one of the answer's number fields, each side names a numeric parameter of the record, one parameter bounds one side of one cell). Authored for usgs-quakes-state and usgs-quakes-near (properties.mag ← min_mag). docs/SCHEMA.md documents it.
• Upcoming calendars fetch from today forward. mlb-team-schedule and finnhub-earnings-calendar filled their date window at −30/0 days while their next_*/upcoming answers read the first row, so every "next game" was a game already played. The clock fill is now 0/+30 for both, as a provider rule in fills.py so a future fills run keeps it, plus the two record lines. Live check: the old window returned a Sept 9 game first for every MLB team; the new one returns the next scheduled game.

Gate (Docker, smartbrain_3000:dev): build 8,672 sources; check 8,674 records, 259 with answers, 0 invalid; lint 0; evallookup 46/46; pytest 268 passed (one new test per change). answers-check passes on both edited answers files.