chore: remove all source code comments and internal artifacts

Strip every comment from the source (parsed with the TypeScript compiler so
strings, template literals, regex literals and JSX are never touched), and drop
internal/working artifacts that do not belong in the public repository
(design mockups, internal analysis docs, a stray backup file and an old log).
No functional change: build is green, the full test suite passes.

tests/utils.test.ts

@@ -92,7 +92,6 @@ describe("utils", () => {
     const result = sanitizeFilename(longName);
     expect(typeof result).toBe("string");
     expect(result.length).toBeGreaterThan(0);
-    // The function should return a non-empty string and not crash
     expect(result).toBe(longName);
   });
 
@@ -100,7 +99,6 @@ describe("utils", () => {
     const result = formatEta(999999);
     expect(typeof result).toBe("string");
     expect(result.length).toBeGreaterThan(0);
-    // 999999 seconds = 277h 46m 39s
     expect(result).toBe("277:46:39");
   });
 
@@ -113,28 +111,22 @@ describe("utils", () => {
 
   it("extracts filenames from URLs with encoded characters", () => {
     expect(filenameFromUrl("https://example.com/file%20with%20spaces.rar")).toBe("file with spaces.rar");
-    // %C3%A9 decodes to e-acute (UTF-8), which is preserved
     expect(filenameFromUrl("https://example.com/t%C3%A9st%20file.zip")).toBe("t\u00e9st file.zip");
     expect(filenameFromUrl("https://example.com/dl?filename=Movie%20Name%20S01E01.mkv")).toBe("Movie Name S01E01.mkv");
-    // Malformed percent-encoding should not crash
     const result = filenameFromUrl("https://example.com/%ZZ%invalid");
     expect(typeof result).toBe("string");
     expect(result.length).toBeGreaterThan(0);
   });
 
   it("handles looksLikeOpaqueFilename edge cases", () => {
-    // Empty string -> sanitizeFilename returns "Paket" which is not opaque
     expect(looksLikeOpaqueFilename("")).toBe(false);
     expect(looksLikeOpaqueFilename("a")).toBe(false);
     expect(looksLikeOpaqueFilename("ab")).toBe(false);
     expect(looksLikeOpaqueFilename("abc")).toBe(false);
     expect(looksLikeOpaqueFilename("download.bin")).toBe(true);
-    // 24-char hex string is opaque (matches /^[a-f0-9]{24,}$/)
     expect(looksLikeOpaqueFilename("abcdef123456789012345678")).toBe(true);
     expect(looksLikeOpaqueFilename("abcdef1234567890abcdef12")).toBe(true);
-    // Short hex strings (< 24 chars) are NOT considered opaque
     expect(looksLikeOpaqueFilename("abcdef12345")).toBe(false);
-    // Real filename with extension
     expect(looksLikeOpaqueFilename("Show.S01E01.720p.mkv")).toBe(false);
   });
 });