Fix grep PCRE patterns to use POSIX character classes

Replace \s with [[:space:]] and drop \b in grep patterns across skill
files and TODO.md. The PCRE tokens silently fail to match in BRE/ERE
mode, defeating the purpose of the pattern checks.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: igerber

.claude/commands/pre-merge-check.md

@@ -33,13 +33,13 @@ If any methodology files changed, run these pattern checks on the **changed meth
 
 **Check A — Inline inference computation**:
 ```bash
-grep -n "t_stat\s*=\s*[^#]*/ *se" <changed-methodology-files> | grep -v "safe_inference"
+grep -n "t_stat[[:space:]]*=[[:space:]]*[^#]*/ *se" <changed-methodology-files> | grep -v "safe_inference"
 ```
 Flag each match: "Consider using `safe_inference()` from `diff_diff.utils` instead of inline t_stat computation."
 
 **Check B — Zero-SE fallback to 0.0 instead of NaN**:
 ```bash
-grep -En "if.*(se|SE).*>.*0.*else\s+(0\.0|0)\b" <changed-methodology-files>
+grep -En "if.*(se|SE).*>.*0.*else[[:space:]]+(0\.0|0)" <changed-methodology-files>
 ```
 Flag each match: "SE=0 should produce NaN, not 0.0, for inference fields."
 

.claude/commands/push-pr-update.md

@@ -127,8 +127,8 @@ When the working tree is clean but commits are ahead, scan for secrets in the co
    ```
 
    If methodology files are present, run Checks A and B from `/pre-merge-check` Section 2.1 on those files:
-   - **Check A**: `grep -n "t_stat\s*=\s*[^#]*/ *se" <methodology-files> | grep -v "safe_inference"`
-   - **Check B**: `grep -En "if.*(se|SE).*>.*0.*else\s+(0\.0|0)\b" <methodology-files>`
+   - **Check A**: `grep -n "t_stat[[:space:]]*=[[:space:]]*[^#]*/ *se" <methodology-files> | grep -v "safe_inference"`
+   - **Check B**: `grep -En "if.*(se|SE).*>.*0.*else[[:space:]]+(0\.0|0)" <methodology-files>`
 
    If warnings are found:
    ```

.claude/commands/submit-pr.md

@@ -139,8 +139,8 @@ Determine if this is a fork-based workflow:
    ```
 
    If methodology files are present, run Checks A and B from `/pre-merge-check` Section 2.1 on those files:
-   - **Check A**: `grep -n "t_stat\s*=\s*[^#]*/ *se" <methodology-files> | grep -v "safe_inference"`
-   - **Check B**: `grep -En "if.*(se|SE).*>.*0.*else\s+(0\.0|0)\b" <methodology-files>`
+   - **Check A**: `grep -n "t_stat[[:space:]]*=[[:space:]]*[^#]*/ *se" <methodology-files> | grep -v "safe_inference"`
+   - **Check B**: `grep -En "if.*(se|SE).*>.*0.*else[[:space:]]+(0\.0|0)" <methodology-files>`
 
    If warnings are found:
    ```

TODO.md

@@ -75,7 +75,7 @@ Several estimators return `0.0` for t-statistic when SE is 0 or undefined. This
 
 **How to find them:**
 ```bash
-grep -n "t_stat\s*=\s*[^#]*/ *se" diff_diff/*.py | grep -v "safe_inference"
+grep -n "t_stat[[:space:]]*=[[:space:]]*[^#]*/ *se" diff_diff/*.py | grep -v "safe_inference"
 ```
 
 **Migration pattern:**