Possible bugs

```
gcc -I. -Wall -c main.c -o main.o
main.c:53:10: warning: unused variable 'p2' [-Wunused-variable]
53 | re_t p2 = re_compile("b"); /* This call corrupts p1's data */
| ^~
1 warning generated.
gcc main.o re.o -o test_bugs
./test_bugs
=== Validating Discovered Errors in tiny-regex-c ===

=== Validating Discovered Errors in tiny-regex-c ===

[BUG FOUND] Empty Match Rejected Pattern: 'a* ' Text: ' ' -> Result: -1 (Bug: Implementation gave -1, but Correct spec says 0)
[BUG FOUND] Anchor Fails Empty Pattern: '$ ' Text: ' ' -> Result: -1 (Bug: Implementation gave -1, but Correct spec says 0)
[BUG FOUND] Connected Range Leak Pattern: '[0-9-a] ' Text: '@ ' -> Result: 0 (Bug: Implementation gave 0, but Correct spec says -1)
[NO BUG ] Silent Truncation Pattern: '^abc$ ' Text: 'ab ' -> Result: -1
[BUG FOUND] Static Clobbering Pattern 'a' failed to match 'a' after compiling 'b'.
[BUG FOUND] Trailing Backslash Pattern: '\ ' Text: 'a ' -> Result: 0 (Bug: Implementation gave 0, but Correct spec says -1)
[BUG FOUND] Signedness Range Pattern: '[a-?] ' Text: 'b ' -> Result: -1 (Bug: Implementation gave -1, but Correct spec says 0)
[BUG FOUND] Ghost Anchor Pattern 'b^' matched 'bA' due to stale memory from 'aA'.

```

[main.c](https://github.com/user-attachments/files/24141984/main.c)

Start with the attached main.c and reproduce the issue using the shown gcc commands and ./test_bugs. Review each reported case—empty matches, anchors, ranges, trailing backslashes, static clobbering, and signedness—and consider the work complete when the observed results match the stated expected results.

Written by the indexing model from the issue text.