fix(chromaterm): replace alternation in lookbehinds for PCRE2 compat

PCRE2 requires fixed-length lookbehinds. The file path regex used
`(?<=[\s(]|^)` (variable-length alternation) and the git hash regex
used `(?<=commit |merge |...)` (different-length alternatives).

Replaced with non-capturing groups containing individual fixed-length
lookbehinds that satisfy the PCRE2 constraint.

Closes #15

Author: AnExiledDev

.devcontainer/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## [Unreleased]
 
+### Fixed
+
+#### ChromaTerm
+- **Regex lookbehinds** — replaced alternation inside lookbehinds (`(?<=[\s(]|^)` and `(?<=commit |merge |...)`) with non-capturing groups containing individual lookbehinds (`(?:(?<=[\s(])|^)` and `(?:(?<=commit )|(?<=merge )|...)`) for PCRE2 compatibility
+
 ### Removed
 
 #### VS Code Extensions

.devcontainer/features/chromaterm/chromaterm.yml

@@ -18,7 +18,7 @@ rules:
   # File paths with optional line numbers (e.g., src/main.py:42)
   # Covers common extensions for languages used in development
   - description: File paths with line numbers
-    regex: '(?<=[\s(]|^)([a-zA-Z0-9_./-]+\.(py|ts|tsx|js|jsx|md|json|yml|yaml|toml|sh|rs|go|sql|css|html|svelte))(:(\d+))?'
+    regex: '(?:(?<=[\s(])|^)([a-zA-Z0-9_./-]+\.(py|ts|tsx|js|jsx|md|json|yml|yaml|toml|sh|rs|go|sql|css|html|svelte))(:(\d+))?'
     color:
       1: f.file_purple underline
       4: f.line_gray
@@ -31,5 +31,5 @@ rules:
 
   # Git short commit hashes (7-12 hex chars)
   - description: Git commit hashes
-    regex: '(?<=commit |merge |pick |revert |fixup )[0-9a-f]{7,40}'
+    regex: '(?:(?<=commit )|(?<=merge )|(?<=pick )|(?<=revert )|(?<=fixup ))[0-9a-f]{7,40}'
     color: f.hash_yellow