refactor: extract shared config-file rewrite loop into Config helper

[dmccoystephenson]

Summary

DRY refactor consolidating the duplicated config-file rewrite logic into a single source of truth.

• Config.saveWindowSize and KeyBindings.saveToConfigFile contained a character-for-character identical read → update-matching-keys → append-new-keys → write-back loop, differing only in how savedValues is built and the log message.
• Extracted the loop into Config._writeKeyValues(self, savedValues, errorMessage) (src/config/config.py). Both callers now build their savedValues dict and delegate; the differing warning text is threaded through errorMessage so existing log behavior is preserved.
• Removed keyBindings.py's now-orphaned getLogger import and module-level _logger — its only use was the warning that moved into Config.

Net −13 LOC across 3 files; keyBindings.saveToConfigFile shrank from ~42 lines to ~8.

Why

Any future change to the rewrite behavior (comment handling, quoting, encoding, atomic write) previously had to be made in two places and was easy to drift — the classic "bug fixed in one copy but not the other" trap.

Test plan

• python3 -m compileall src -q — clean
• SDL_VIDEODRIVER=dummy SDL_AUDIODRIVER=dummy python3 -m pytest — 461 passed (was 460; +1 new)
• Regression coverage: the existing test_config.py (saveWindowSize) and test_keyBindings.py (saveToConfigFile) suites exercise the extracted helper through both public callers — update-in-place, append, whitespace-before-colon, comment preservation, round-trip — and all still pass unchanged.
• Added test_write_key_values_updates_appends_and_preserves exercising the helper directly (update + append + comment/blank-line preservation in one call).
• Formatting run scoped to the 3 changed files only (not tree-wide format.sh), so no unrelated drift entered the diff.

Deferred this cycle (skip reasons)

• refactor: room save-file path is built five times across four files while two unused helper methods already exist #373 (room save-file path duplicated 5×) — the other refactor candidate; deferred because it spans 4 files including a persistence path (higher blast radius) and pairs naturally with the bug: a corrupt or truncated save file crashes the game on load — json.load is unguarded and writes are non-atomic #370 atomic-write work, so it warrants its own focused PR.
• docs: copilot-instructions.md repository layout and Pillow version are stale #362 (copilot-instructions.md staleness), config.yml is out of sync with the code: 2 keys are read but never used, 2 keys the code reads are missing #365 (config.yml drift) — touch do-not-auto-merge paths; better in their own PRs.
• bug: a corrupt or truncated save file crashes the game on load — json.load is unguarded and writes are non-atomic #370, Save: schema validation failures are logged but invalid data is still written to disk #363 (save-corruption / schema-write bugs) — larger; need atomic-write design and dedicated regression tests.
• test: Room.tickExcrement and Inventory.hasAvailableSlotFor have no coverage #372, test: MapImageGenerator coordinate math and bounds logic are uncovered #367, test: add unit tests for WorldScreenPersistence (save/load currently uncovered) #364, robustness: a missing or unreadable asset crashes the render loop via DrawableEntity.getImage #368 (coverage / robustness) — out of this PR's theme.
• Backlog Add storage containers #346, Prevent floors from being placed on floors #345, Persist HUD element layout between sessions #338, Provide text-based UI option #239, Delegate spatial mechanics to Viron server #234, Expose REST endpoint for client applications #231 — feature/architecture work out of scope.

Closes #366

🤖 Generated with Claude Code

[dmccoystephenson]

Self-review rubric (scored adversarially against the diff; CI is the external anchor):

• Scope: PASS — 4 files, each necessary for #366 or the required CHANGELOG. The keyBindings.py logger removal is not unrelated churn: _logger/getLogger were orphaned by moving the only warning into Config. Formatting was run scoped to the 3 changed files, so no unrelated drift entered the diff.
• Tests-new: PASS — the new Config._writeKeyValues helper has a direct test (test_write_key_values_updates_appends_and_preserves, covering update-in-place + append + comment preservation) plus indirect coverage through both public callers.
• Behavior preservation: PASS — the extracted loop is byte-for-byte the original; saveWindowSize and saveToConfigFile build the same savedValues and pass their original log message through errorMessage. Full suite 461 passed (was 460), including the unchanged saveWindowSize/saveToConfigFile regression suites.
• Sibling structure: PASS — _writeKeyValues follows the codebase's protected-method convention (leading underscore + camelCase, as in _buildRoomFilePath, _loadOrGenerateRoom); the new test mirrors the existing tmp_path/monkeypatch pattern in test_config.py.
• Issue resolution: PASS — both named surfaces (config.py:243, keyBindings.py:129) are changed and the loop is now single-sourced.
• CI: PASS — the test check is green on the PR head.
• No @property / no new print() / no container import in class files / vendored src/lib untouched: PASS — confirmed via grep over added lines.
• CHANGELOG updated: PASS — dated [integrated] entry; notes the cycle-2 scoped-formatting lesson was applied.

One judgment call (deferred, not changed here): KeyBindings.saveToConfigFile calls config._writeKeyValues(...), which reaches a single-underscore (protected) method on a different class. This is mildly unidiomatic, but it is the exact API proposed in issue #366 (Config._writeKeyValues with KeyBindings delegating to it), and Config is the natural owner of config-file I/O (it owns getConfigFilePath). A public name (e.g. writeKeyValuesToConfigFile) would avoid the protected-access smell; kept as specced and flagged for reviewer preference.