Fix result_parser: null body guard, explicit dispatch, TypeError messages, dead code

[t0kubetsu]

Summary

Fixes #145. Three correctness bugs and two code-quality issues in result_parser.py.

Changes

Null body guard

parse_json chained .get("body").get(...) without null guards. Any document with a missing or None body key raised TypeError/AttributeError, crashing the export tick. Now extracted to body = doc.get("body") or {} and ports = body.get("ports") or [] at the top of the function.

Explicit dispatch dict

globals()[action] was used to look up parser functions. Replaced with _PARSER_DISPATCH, a module-level dict explicitly mapping each ALLOW-listed name to its function. Prevents silent divergence between ALLOW and globals(). Added a hsh stub (NotImplementedError) so the table is complete.

TypeError messages

Bare raise TypeError (no message, no instance) at lines 621 and 633 replaced with descriptive messages. Also fixed ruff E713: not x in y → x not in y.

Loop variable shadowing

Loop variable script was immediately rebound to the dict value on the next line, producing a confusing for script in body: ... script = body.get(script) pattern. Renamed to script_key/script_data.

Dead code removal

insensitive() function removed — not in ALLOW, not imported anywhere, unreachable since v0.2606.0.

Test plan

• Submit a scan result with body=None — verify export tick does not crash
• Submit a scan result with missing ports key — verify graceful handling
• Verify all 11 parser actions in ALLOW remain callable via _PARSER_DISPATCH

[t0kubetsu]

Fixed hsh() stub: changed NotImplementedError to return {} — hsh is in default_parsing so raising would crash the export tick for documents with http-header.output.