feat: implement real-time game state JSON export with GitHub Gist sync

[DrCord]

Summary

This is PR 2 of 5 splitting #122 into reviewable chunks.

Covers items 1, 2, 5, and 6 from the PR summary. This is the main piece — the stfc_summary and GitHub Pages viewer PRs depend on it.

Depends on: PR 1 (feature/id-mappings) — the id_mappings module must be present for this to build.

Note on items 1 & 2: Real-time JSON export (item 1) and GitHub Gist sync (item 2) are implemented together in game_state_export.cc. The Gist sync was introduced early in development and is deeply integrated with the export loop; separating it cleanly would require a significant refactor of that file. They are presented together here as the core C++ feature.

Changes

New: game_state_export module (items 1, 2, 5, 6)

mods/src/patches/parts/game_state_export.h/cc — Background export thread (10-second debounce on data change) that writes per-category JSON files:

• player.json, ships.json, resources.json, research.json, officers.json
• buildings.json, faction.json, buffs.json, territory.json
• missions.json, queues.json, manifest.json

Gist sync (item 2): sync_all_to_gist() batches all files into a single GitHub Gist PATCH on each export cycle, rate-limited to avoid API abuse.

Per-ship cargo stats (item 5): Each entry in ships.json includes cargo_capacity and cargo_protection sourced from ShipTierSpec.

Peace shield capture (item 6): capture_peace_shield() captures expiry epoch and token count from both the inventory path and StarbaseDetailedScan, with guards preventing stale/zero values from overwriting valid cached state.

Modified: sync.cc
Existing sync hooks extended to call game_state_export::capture_*() functions for player data, resources, ships, research, officers, buildings, missions, factions, territory, and queues.

Modified: config.cc/h, defaultconfig.h
New [sync.game_state] and [sync.game_state.github] TOML sections with keys for enabling the export, output path, player ID, and Gist credentials/filenames.

Modified: file.cc/h, patches.cc

• file.cc: Resolves all default file paths relative to the prime.exe directory on Windows
• patches.cc: Wires up InstallGameStateExport() hook

Other

• example_community_patch_settings.toml: Updated with all new config keys
• .github/workflows/, xmake.lua, macOS build files: Project renamed to stfc-community-mod; CI and macOS launcher improvements
• scripts/: End-to-end test, Gist verification, battle log checker, player export validator

Dependency chain

main
└── feature/id-mappings             (PR 1)
    └── feature/core-game-state-export  ← this PR
        └── feature/stfc-summary    (PR 3)
            └── feature/github-pages-viewer (PR 4)

Test plan

• Project builds on Windows and macOS with no new compile errors
• After configuring [sync.game_state], export files appear in the configured directory during a game session
• scripts/check_player_export.py validates the structure of player.json
• scripts/verify_gist_sync.py confirms all files are uploaded to the configured Gist
• Peace shield expiry in player.json matches the in-game display and does not reset mid-session