Add enhanced text sanitization (#83)

* Add enhanced text sanitization

* Format code with prettier

* Refactor tests to remove redundancy and improve structure

- Remove redundant 'mixed input patterns' test from sanitizer.test.ts
- Consolidate integration tests into 2 focused real-world scenarios
- Add HTML comment stripping to sanitizeContent function
- Update test expectations to match sanitization behavior
- Maintain full coverage with fewer, more focused tests

* Fix prettier formatting

* Remove rendered.html from repository

* Remove test-markdown.json and update .gitignore

* Revert .gitignore changes

test/integration-sanitization.test.ts

@@ -0,0 +1,134 @@
+import { describe, expect, it } from "bun:test";
+import { formatBody, formatComments } from "../src/github/data/formatter";
+import type { GitHubComment } from "../src/github/types";
+
+describe("Sanitization Integration", () => {
+  it("should sanitize complete issue/PR body with various hidden content patterns", () => {
+    const issueBody = `
+# Feature Request: Add user dashboard
+
+## Description
+We need a new dashboard for users to track their activity.
+
+<!-- HTML comment that should be removed -->
+
+## Technical Details
+The dashboard should display:
+- User statistics ![dashboard mockup with hidden​‌‍text](dashboard.png)
+- Activity graphs <img alt="example graph description" src="graph.jpg">
+- Recent actions
+
+## Implementation Notes
+See [documentation](https://docs.example.com "internal docs title") for API details.
+
+<div data-instruction="example instruction" aria-label="dashboard label" title="hover text">
+  The implementation should follow our standard patterns.
+</div>
+
+Additional notes: Text­with­soft­hyphens and &#72;&#105;&#100;&#100;&#101;&#110; encoded content.
+
+<input placeholder="search placeholder" type="text" />
+
+Direction override test: ‮reversed‬ text should be normalized.`;
+
+    const imageUrlMap = new Map<string, string>();
+    const result = formatBody(issueBody, imageUrlMap);
+
+    // Verify hidden content is removed
+    expect(result).not.toContain("<!-- HTML comment");
+    expect(result).not.toContain("hidden​‌‍text");
+    expect(result).not.toContain("example graph description");
+    expect(result).not.toContain("internal docs title");
+    expect(result).not.toContain("example instruction");
+    expect(result).not.toContain("dashboard label");
+    expect(result).not.toContain("hover text");
+    expect(result).not.toContain("search placeholder");
+    expect(result).not.toContain("\u200B");
+    expect(result).not.toContain("\u200C");
+    expect(result).not.toContain("\u200D");
+    expect(result).not.toContain("\u00AD");
+    expect(result).not.toContain("\u202E");
+    expect(result).not.toContain("&#72;");
+
+    // Verify legitimate content is preserved
+    expect(result).toContain("# Feature Request: Add user dashboard");
+    expect(result).toContain("## Description");
+    expect(result).toContain("We need a new dashboard");
+    expect(result).toContain("User statistics");
+    expect(result).toContain("![](dashboard.png)");
+    expect(result).toContain('<img src="graph.jpg">');
+    expect(result).toContain("[documentation](https://docs.example.com)");
+    expect(result).toContain(
+      "The implementation should follow our standard patterns",
+    );
+    expect(result).toContain("Hidden encoded content");
+    expect(result).toContain('<input type="text" />');
+  });
+
+  it("should sanitize GitHub comments preserving discussion flow", () => {
+    const comments: GitHubComment[] = [
+      {
+        id: "1",
+        databaseId: "100001",
+        body: `Great idea! Here are my thoughts:
+
+1. We should consider the performance impact
+2. The UI mockup looks good: ![ui design](mockup.png)
+3. Check the [API docs](https://api.example.com "api reference") for rate limits
+
+<div aria-label="comment metadata" data-comment-type="review">
+  This change would affect multiple systems.
+</div>
+
+Note: Implementation​should​follow​best​practices.`,
+        author: { login: "reviewer1" },
+        createdAt: "2023-01-01T10:00:00Z",
+      },
+      {
+        id: "2",
+        databaseId: "100002",
+        body: `Thanks for the feedback! 
+
+<!-- Internal note: discussed with team -->
+
+I've updated the proposal based on your suggestions.
+
+&#84;&#101;&#115;&#116; &#110;&#111;&#116;&#101;: All systems checked.
+
+<span title="status update" data-status="approved">Ready for implementation</span>`,
+        author: { login: "author1" },
+        createdAt: "2023-01-01T12:00:00Z",
+      },
+    ];
+
+    const result = formatComments(comments);
+
+    // Verify hidden content is removed
+    expect(result).not.toContain("<!-- Internal note");
+    expect(result).not.toContain("api reference");
+    expect(result).not.toContain("comment metadata");
+    expect(result).not.toContain('data-comment-type="review"');
+    expect(result).not.toContain("status update");
+    expect(result).not.toContain('data-status="approved"');
+    expect(result).not.toContain("\u200B");
+    expect(result).not.toContain("&#84;");
+
+    // Verify discussion flow is preserved
+    expect(result).toContain("Great idea! Here are my thoughts:");
+    expect(result).toContain("1. We should consider the performance impact");
+    expect(result).toContain("2. The UI mockup looks good: ![](mockup.png)");
+    expect(result).toContain(
+      "3. Check the [API docs](https://api.example.com)",
+    );
+    expect(result).toContain("This change would affect multiple systems.");
+    expect(result).toContain("Implementationshouldfollowbestpractices");
+    expect(result).toContain("Thanks for the feedback!");
+    expect(result).toContain(
+      "I've updated the proposal based on your suggestions.",
+    );
+    expect(result).toContain("Test note: All systems checked.");
+    expect(result).toContain("Ready for implementation");
+    expect(result).toContain("[reviewer1 at");
+    expect(result).toContain("[author1 at");
+  });
+});