T07: agentic realization over a stdlib browser surface

Two decisions taken with the operator: stdlib HTML driver instead of
Playwright (F-0004), and a deterministic discovery runtime instead of a live
model. Both sit behind interfaces so the alternatives drop in later.

- html.py: stdlib DOM parse and query
- agentic.py: DiscoveryRuntime (agentic arm, ignores data-td by construction)
  and RecordedSelectorRuntime (control arm, uses the strongest identifier the
  page offers)
- browser.py: per-actor sessions over real HTTP, constructed per call so no
  actor inherits another's connection state
- cost/nondeterminism metrics recorded from the first run

F-0005 (CONCEPT_DRIFT): the H-001 result is a narrowing. Where test ids are
preserved, discovery 9/9 and recorded selectors 9/9 - the semantic action buys
nothing. Where they are dropped, discovery 2/3 and recorded 0/3. The concept
model presents semantic actions as generally superior; the evidence says
conditionally superior.

M21 and M22 added mid-task: the deciding side of the axis was N=1. M22 (field
names renamed) defeats the heuristic and is the first concrete evidence that a
live model would add capability, not just cost.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 1629012@bnt-lap001
Assistant-Session: 78d4fb13-8a1e-474b-87a3-9b9261c49a39

research/hypotheses/H-002-mechanical-adaptation.md

@@ -1,7 +1,7 @@
 ---
 id: H-002
 title: Mechanical Adaptation
-status: PROPOSED
+status: EXPERIMENTING
 created: "2026-08-22"
 experiments: [E-001]
 concepts: [C-adaptation]
@@ -33,8 +33,20 @@ at all.
   (`docs/TestDriverClassificationDesign.md` D-02). Any non-empty diff is both a
   falsification signal **and** a framework defect, since no write path should exist.
 
+## Result so far (TD-WP-0002-T07)
+
+Discovery recovered from 11 of 12 mechanical mutations with **no claim or
+invariant diff in any run**, as D-02 requires structurally. The single failure
+(M22, field names renamed) failed *loudly* — a `RealizationFailed` recorded in
+evidence, not a silent pass. That distinction is the one that matters: the
+framework reported that it could not act, rather than reporting that nothing was
+wrong.
+
+Full classification of recovery vs defect is T08.
+
 ## Status log
 
-- 2026-08-22 `PROPOSED`. Design decision D-02 makes the second falsification
+- 2026-08-22 `PROPOSED`.
+- 2026-08-22 `EXPERIMENTING`. Recovery demonstrated; classification pending T08. Design decision D-02 makes the second falsification
   branch structurally unreachable; the measurement is retained anyway, as an
   assertion that the architecture is what we believe it is.