Add Technical_Decomp_Ignore

Technical_Decomp_Ignore.md

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+## enroll/ignore.py
+
+### IgnorePolicy (dataclass)
+
+#### Purpose: the “don’t accidentally harvest secrets” gatekeeper.
+
+#### Fields:
+
+- deny_globs: list of fnmatch patterns that are always denied (unless dangerous=True)
+- defaults include /etc/shadow, /etc/ssl/private/*, SSH host keys, letsencrypt, etc.
+- allow_binary_globs: explicit allowlist of binary-ish config artifacts (APT keyrings etc.)
+- max_file_bytes: hard cap; default 256 KB
+- sample_bytes: how many bytes to inspect for content heuristics; default 64 KB
+- dangerous: if True, relaxes some safety checks
+
+#### Methods:
+
+##### __post_init__
+
+If deny_globs or allow_binary_globs weren’t passed, it fills them with the defaults.
+
+##### iter_effective_lines(content: bytes)
+
+Yields “meaningful” lines from a bytes blob by skipping:
+
+- empty lines
+- line comments starting with #, ;, //, or *
+- C-style block comments /* ... */ (best-effort state machine)
+
+This is used so secret scanning doesn’t trigger on commented-out examples.
+
+##### deny_reason(path: str) -> Optional[str]
+
+Returns a short deny code if the file should not be harvested; otherwise None.
+
+The decision pipeline is:
+
+- If path.endswith(".log") → "log_file" always denied.
+- If not dangerous:
+    - if path matches any deny glob → "denied_path"
+- os.stat() (follow symlinks):
+    - if stat fails → "unreadable"
+    - if size > max_file_bytes → "too_large"
+    - if not a regular file or is symlink → "not_regular_file"
+- Read up to sample_bytes:
+    - if read fails → "unreadable"
+- Binary-like detection:
+    - if the sample contains NUL (b"\x00"):
+        - if path matches allow-binary globs → allowed
+        - else → "binary_like"
+    - Note: this binary check still applies even in dangerous=True.
+- If not dangerous:
+    - scan “effective lines” against regex patterns like:
+        - PEM private key headers
+        - password = ...
+        - keywords (token, secret, api_key, etc.)
+    - if matched → "sensitive_content"
+
+If nothing triggers, return None (allowed).