feat(spike): implement save/load hook feasibility

[SolshineCode]

Implements save/load hook feasibility spike with complete test suite.

[gemini-code-assist]

Code Review

This pull request introduces the Product Requirements Document and initial feasibility spikes for Claude Kingdoms, featuring Python scripts for save injection and a Java-based observability manager. The review identified critical bugs, including malformed XML in the Maven configuration, an incorrectly formatted ZIP save file, and a character-vs-byte length error in the HTTP server implementation. Further improvements were suggested regarding file encoding consistency, the removal of hardcoded absolute paths for better portability, and alignment with Java naming conventions for boolean getters.

[gemini-code-assist]

The file test_save.zip contains raw JSON text. According to the PRD and Unciv's format, a save file should be a ZIP archive containing a file named savegame. This file will likely fail to load in the game engine.

[gemini-code-assist]

Typo in the closing tag for <name>. It should be </name> instead of </modelVersion>.

    <name>Observability Hook Feasibility Spike</name>

[gemini-code-assist]

Invalid XML syntax <parameter=. This should likely be the opening tag for <properties>. Also, the file appears to be missing the closing </properties> and </project> tags.

    <properties>

[gemini-code-assist]

The log directory path is hardcoded to a specific absolute path on your local machine. This makes the script non-portable. Consider using a relative path or making it configurable via an environment variable.

Suggested change

	log_dir = Path("/mnt/c/Users/caleb/projects/ClaudeKingdoms/spikes/hook_logs")
	log_dir = Path(__file__).parent.parent / "spikes" / "hook_logs"

[gemini-code-assist]

response.length() returns the number of characters, but sendResponseHeaders requires the length in bytes. This can cause issues with multi-byte characters (e.g., UTF-8). It's safer to convert the string to bytes first and use the byte array's length.

    private void sendResponse(HttpExchange exchange, int statusCode, String response) throws IOException {
        byte[] responseBytes = response.getBytes(java.nio.charset.StandardCharsets.UTF_8);
        exchange.sendResponseHeaders(statusCode, responseBytes.length);
        try (OutputStream os = exchange.getResponseBody()) {
            os.write(responseBytes);
        }
    }

[gemini-code-assist]

FileWriter uses the default system encoding, which can lead to issues when moving save files between different operating systems. It is better to explicitly specify StandardCharsets.UTF_8.

Suggested change

	try (FileWriter writer = new FileWriter(saveFile)) {
	writer.write(json);
	}
	try (java.io.Writer writer = new java.io.OutputStreamWriter(new java.io.FileOutputStream(saveFile), java.nio.charset.StandardCharsets.UTF_8)) {
	writer.write(json);
	}

[gemini-code-assist]

When reading the save file, the default encoding is used. To ensure consistency with the writer, explicitly use StandardCharsets.UTF_8.

Suggested change

	String json = new String(Files.readAllBytes(Paths.get(saveFile.getAbsolutePath())));
	String json = new String(Files.readAllBytes(Paths.get(saveFile.getAbsolutePath())), java.nio.charset.StandardCharsets.UTF_8);

[gemini-code-assist]

The getter name isHasActed is redundant and doesn't follow standard Java naming conventions for booleans. hasActed() or isActed() would be more idiomatic.

Suggested change

	public boolean isHasActed() { return hasActed; }
	public boolean hasActed() { return hasActed; }