* test(#1961): add failing-first bug-taxonomy routing contract tests
Epic #1957 Phase 2B. Source-text-is-the-product contract tests (3 taxonomy
classes, explicit class->technique routing table, Bohrbug->repro+SBFL+bisect,
Heisenbug->record-replay/stability+SKIP-SBFL, Concurrency->atomicity/order/
deadlock checklist, bug_class in DEBUG Current Focus, supersede-not-append)
plus a routing-table specification object pinning the documented decisions
(SBFL forbidden on Heisenbug is the load-bearing 1B/2B seam).
Failing-first: reference, Phase 1.75, and routing-table reframe do not yet exist.
* feat(#1961): add bug-taxonomy classification + strategy routing to gsd-debugger
Epic #1957 Phase 2B (reliability-critical). Adds Phase 1.75: classify the
failure as Bohrbug / Heisenbug-Mandelbug / Concurrency, then route the
investigation technique via an explicit class->technique table (Kernighan: no
opaque heuristic). Bohrbug -> reproduction + SBFL (Phase 1.25) + git bisect;
Heisenbug/Mandelbug -> record-replay (rr) + stability-stress + statistical
sampling, with SBFL explicitly SKIPPED (a flaky spectrum poisons the Ochiai
ranking — the load-bearing 1B/2B seam); Concurrency -> the
atomicity/order/deadlock checklist first.
Reframes (supersedes, not appends — Zawinski) the flat 'Technique Selection by
situation' table into a class-routed table; the 11 techniques remain as routed
targets. bug_class recorded in Current Focus (DEBUG template); common-bug-
patterns catalog cross-referenced to the taxonomy.
Full rules extracted to gsd-core/references/debugger-bug-taxonomy.md. INVENTORY
+ manifest + agent-size baseline + install-parity goldens + AGENTS.md updated.
* fix(#1961): address orthogonal review (phase-name drift, General lane, revoke framing, row-scoped tests, bounding)
- HIGH: reference said 'Phase 1B' (epic shorthand); corrected to the deployed
'Phase 1.25' (matches the agent + SBFL reference).
- HIGH: 6 of 11 techniques (Rubber duck, Delta, Working backwards,
Differential, Comment-out, Follow-the-indirection) were orphaned by the
situation-table reframe. Added a 'General (any class, situation-cued)'
lane to BOTH the reference routing table and the agent's Technique
Selection table that re-homes them — supersede-not-append now holds.
- MEDIUM: the SBFL-skip is structurally retroactive (Phase 1.25 runs before
Phase 1.75 classification), so reframed the table column from 'Do NOT use'
to 'Revoke if already run' + an explicit 'retroactive revocation, not
proactive skip' note stating the ordering honestly.
- MEDIUM: contract tests are now row-scoped (parse the table by class, assert
per-row) instead of presence-only; added a guard that the previously-
orphaned techniques now have a General-lane route.
- LOW: pinned the canonical bug_class value form (lowercase-kebab:
bohrbug|heisenbug-mandelbug|concurrency; prose may use title-case).
- NIT: added a 'Bound the Heisenbug-chase runs' note (rr/stability/sampling
timeouts) per the unbounded-subprocess gauntlet.
* chore(#1961): backfill changeset pr number (PR #2407)
