fix(cj-scan): suppress detection inside nested non-cj begin_* blocks

cj-scan.py matched =#+begin_src cj:= / =#+end_src= line-by-line without awareness of enclosing block scopes. A cj fence embedded inside =#+begin_example= (typical when documenting what the <cj yasnippet emits) or =#+begin_src snippet= (the yasnippet definition itself) was misclassified as a live cj annotation. Two false positives surfaced from a /respond-to-cj-comments run against an org file with yasnippet docs.

Track an active wrapper_type. When the scanner sees =#+begin_<type>= for any type other than cj: (the cj-open regex is checked first), enter a wrapper state where every line is content until the matching =#+end_<type>= closer fires. Inside a wrapper, both fence patterns and legacy inline cj: lines stay suppressed. Added the TestCjScanNestedFencesIgnored class with 6 tests: nesting inside example, src <other-lang>, and quote; regression guards for clean wrapper close and unclosed-wrapper non-swallow. Canonical pytest: 302 passed, 1 skipped.

1 files changed, 25 insertions, 0 deletions

diff --git a/claude-templates/.ai/scripts/cj-scan.py b/claude-templates/.ai/scripts/cj-scan.py
index 54e2bf9..275f5ca 100644
--- a/claude-templates/.ai/scripts/cj-scan.py
+++ b/claude-templates/.ai/scripts/cj-scan.py
@@ -30,6 +30,7 @@ VALID_VERIFY_DEPTHS = {2, 3}
 HEADING_RE = re.compile(r"^(\*+)\s+(.*)$")
 SRC_OPEN_RE = re.compile(r"^\s*#\+begin_src\s+cj:\s*(\S*)\s*$", re.IGNORECASE)
 SRC_CLOSE_RE = re.compile(r"^\s*#\+end_src\s*$", re.IGNORECASE)
+BLOCK_OPEN_RE = re.compile(r"^\s*#\+begin_(\w+)(?:\s.*)?$", re.IGNORECASE)
 LEGACY_CJ_RE = re.compile(r"^\s*cj:\s*(.*)$")
 VERIFY_KEYWORD_RE = re.compile(r"^VERIFY(\s|\[|$)")
 
@@ -66,6 +67,13 @@ def scan_file(path: Path) -> dict[str, object]:
     block_label: str | None = None
     block_body: list[str] = []
 
+    # Tracks a non-cj `#+begin_<type>` wrapper currently in scope.  Inside a
+    # wrapper, cj fence patterns are *content* (documentation examples,
+    # quoted prose, snippet definitions) -- not annotations -- so we
+    # suppress matching until the wrapper closes.  The closer is type-keyed:
+    # `#+end_example` for example, `#+end_src` for src, etc.
+    wrapper_type: str | None = None
+
     file_str = str(path)
     lines = path.read_text().splitlines()
 
@@ -90,6 +98,15 @@ def scan_file(path: Path) -> dict[str, object]:
                 block_body.append(line)
             continue
 
+        if wrapper_type is not None:
+            wrapper_close_re = re.compile(
+                rf"^\s*#\+end_{re.escape(wrapper_type)}\s*$",
+                re.IGNORECASE,
+            )
+            if wrapper_close_re.match(line):
+                wrapper_type = None
+            continue
+
         m_heading = HEADING_RE.match(line)
         if m_heading:
             depth = len(m_heading.group(1))
@@ -110,6 +127,9 @@ def scan_file(path: Path) -> dict[str, object]:
                 })
             continue
 
+        # cj-open must be checked before the generic begin-block match: a
+        # `#+begin_src cj: ...` line matches both patterns, and cj-open is
+        # the more specific intent.
         m_src_open = SRC_OPEN_RE.match(line)
         if m_src_open:
             in_cj_block = True
@@ -118,6 +138,11 @@ def scan_file(path: Path) -> dict[str, object]:
             block_body = []
             continue
 
+        m_block_open = BLOCK_OPEN_RE.match(line)
+        if m_block_open:
+            wrapper_type = m_block_open.group(1).lower()
+            continue
+
         m_legacy = LEGACY_CJ_RE.match(line)
         if m_legacy:
             cj_blocks.append({