fix(output-encoding): ask about the server half, and say what the family cannot decide

The census recorded this family completing 44 questions on a Node application and finding
nothing, which is what a client-only vocabulary must do there: all six declared sinks were DOM
sinks. NodeGoat's cross-site scripting is server-side.

Decision: the family asks about a value reaching a rendering call, and states in its own
declaration that it cannot decide template-mediated escaping. Whether res.render is safe depends
on the engine's autoescape setting and on the template's markup, neither of which is at the
call, so res.render is not a sink and the family's limits field says so. A new CWE-79 sink
covers res.write, res.end, res.send and the response.* spellings; res.json stays out because an
application/json body is not a document.

Template auto-escaping is claimed where its evidence is, as a configuration defect:
swig.setDefaults, nunjucks.configure and marked.setOptions are security settings now.

It establishes a finding: app/routes/research.js:25, model_entailed,
`req.query.url + req.query.symbol -> res.write(body)`. The handler fetches a URL the caller
chooses and writes the response body into a text/html response, so the document served from
this origin is the attacker's. The record states how coarse the step is: the path from url to
body runs through the client's callback parameter, which the graph treats as reachable from the
call's arguments, so the conclusion rests on the call's semantics rather than on what the graph
established. Five of seven families now establish findings.

Four defects were found on the way, three of them false positives this change would otherwise
have shipped.

- The permissive-value set was shared across every setting, while a boolean's polarity belongs
  to the setting: true leaves the door open in cors({origin: true}) and closes it in
  swig.setDefaults({autoescape: true}). Adding the template engines would have reported the fix
  as the defect on the line that offers it. ConfigSpec now carries per-setting values, and
  Jinja2's Environment moved out of Python's shared list for the same latent reason.
- config.sc matched a dotted setting on its trailing segment alone, so marked.setOptions would
  have claimed an editor's setOptions. dominance.sc already required the qualifier.
- taint.sc asked its flow query of every argument including the receiver at index 0. On a
  response sink the receiver is the response object, so res.end() -- which takes no data -- was
  reported exactly like the res.write(body) two lines above it. Flows now use the real
  arguments, as arity already did.
- The arbiter sorted a file's settings by line number as TEXT, so line 126 preceded line 78 and
  which setting a file reported depended on the spelling of its line numbers.

Template escaping disabled at server.js:135 is detected, measured model_entailed against the
real query and the real arbiter, and still not reported: the arbiter returns one verdict per
question and that file has an earlier permissive setting. Task 14.6 carries it rather than
hiding it.

1,415 tests pass, thirteen skipped; nine Joern-gated query tests pass in the image.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

.kiro/specs/pre-push-safety-net/status.md

@@ -152,11 +152,21 @@ the word `set` in a code comment, matched because the sink text clause searched
 assignment node. Nothing about this changes the release gates. No capability is qualified by
 these subjects.
 
-The first of the three gaps is closed. The untrusted-destination vocabulary now holds the
-client surface a Node server actually calls, and NodeGoat's SSRF is reported at
-`app/routes/research.js:16` with a witness naming the call. One data change, no query change,
-every other family unchanged. Output encoding and access control remain open as tasks 14.3
-and 14.4.
+Two of the three gaps are closed. The untrusted-destination vocabulary now holds the client
+surface a Node server actually calls, and NodeGoat's SSRF is reported at
+`app/routes/research.js:16` with a witness naming the call. Output encoding now asks about the
+server half of its own family and establishes a finding at `app/routes/research.js:25`, and it
+states in its declaration that template-mediated escaping is not something it can decide. Five
+of seven families now establish findings; access control remains open as task 14.4.
+
+Closing the second gap surfaced four defects, three of which were false positives it would
+otherwise have shipped: a permissive-value set shared across settings whose booleans have
+opposite polarity, a dotted setting matched on its trailing segment alone, a flow query asked of
+a call's receiver as well as its arguments, and a file's settings ordered by the spelling of
+their line numbers. Template auto-escaping disabled at `server.js:135` is detected and still not
+reported, because the arbiter returns one verdict per question and that file has an earlier
+permissive setting; task 14.6 carries it.
 
 Evidence: [family detection census](../../../benchmarks/measurements/2026-09-19-family-detection-census.json),
-[untrusted destination vocabulary](../../../benchmarks/measurements/2026-09-19-untrusted-destination-vocabulary.json).
+[untrusted destination vocabulary](../../../benchmarks/measurements/2026-09-19-untrusted-destination-vocabulary.json),
+[output encoding family](../../../benchmarks/measurements/2026-09-19-output-encoding-family.json).