fix: resolve markdownlint MD028 and ESLint eqeqeq warnings

Fix two lint issues that cause `npm run lint` to exit non-zero:

1. README.md (MD028): Two consecutive blockquotes separated by a bare
   blank line. Markdownlint treats this as one blockquote with an
   illegal blank line inside. Replace the blank line with a `>`
   continuation so both paragraphs stay in the same blockquote.

2. session-activity-tracker.js (eqeqeq): Three instances of `== null`
   replaced with explicit `=== null || === undefined` guards to satisfy
   the repo's `eqeqeq: warn` ESLint rule.

Closes #1366

README.md

@@ -179,7 +179,7 @@ Get up and running in under 2 minutes:
 ### Step 2: Install Rules (Required)
 
 > WARNING: **Important:** Claude Code plugins cannot distribute `rules` automatically. Install them manually:
-
+>
 > If your local Claude setup was wiped or reset, that does not mean you need to repurchase ECC. Start with `ecc list-installed`, then run `ecc doctor` and `ecc repair` before reinstalling anything. That usually restores ECC-managed files without rebuilding your setup. If the problem is account or marketplace access for ECC Tools, handle billing/account recovery separately.
 
 ```bash

scripts/hooks/session-activity-tracker.js

@@ -55,7 +55,7 @@ function sanitizeParamValue(value, depth = 0) {
     return '[Truncated]';
   }
 
-  if (value == null) {
+  if (value === null || value === undefined) {
     return value;
   }
 
@@ -502,7 +502,7 @@ function summarizeInput(toolName, toolInput, filePaths) {
   if (toolInput && typeof toolInput === 'object') {
     const shallow = {};
     for (const [key, value] of Object.entries(toolInput)) {
-      if (value == null) {
+      if (value === null || value === undefined) {
         continue;
       }
       if (typeof value === 'string' || typeof value === 'number' || typeof value === 'boolean') {
@@ -517,7 +517,7 @@ function summarizeInput(toolName, toolInput, filePaths) {
 }
 
 function summarizeOutput(toolOutput) {
-  if (toolOutput == null) {
+  if (toolOutput === null || toolOutput === undefined) {
     return '';
   }