Library cleanup, responsive panels, and safer imports

Find and clean up short games

Added Special filters to Saved Games, with Fewer than 2 full moves as its first option. It matches games with fewer than four played half-moves and works with the other filters and Select all matching.
Added Clear filters immediately to the right of Filters. It appears when a filter is active and resets all filters together while retaining the chosen sort order.

Made the two main panels adjust automatically as the browser resizes. The live board grows to fit the available vertical space; the Moves, Prediction and Analysis panel fills the remaining width.
Added a gray Maximize / Restore button to Training Profiles. Restore returns the window to its previous size and position.

Added ZIP selection through Browse… and drag-and-drop imports. PGN files inside the ZIP, including files in folders, use the existing game-selection and duplicate-detection workflow.
Discarded imported PGN games with fewer than two full moves (four half-moves) and added a separate discarded-game count to the import result.
Added PGN size, game-count, move-count and nesting limits, including a 64 MiB collection limit, up to 100,000 games, and 1 MiB per game. Invalid or excessive input shows an error.
Replaced repeated variation scanning with single-pass move counting and moved selected games into the paced import queue without retaining another full copy. Comments, variations and duplicate detection remain supported.

Added global and per-client FICS connection limits, command and output budgets, and deadlines for login, stalled writes, unread output, idle connections and session lifetime.
Preserved guest and registered sign-in, console commands and game observation. These changes protect bridge resources; the legacy FICS transport is unchanged.