ci: release workflow test gate is dead — continue-on-error forces conclusion=success; flip to outcome + make CI suite honestly green

[rahlk]

PROBLEM

The release workflow's test gate is dead code and has never fired. .github/workflows/release.yml runs tests with continue-on-error: true (line 44) and gates tag deletion on steps.test.conclusion == 'failure' (line 48) — but under continue-on-error, a failed step's conclusion is forced to success (only outcome records the failure). Verified on real runs: v1.4.0 and v1.4.1 both had failing tests in the Run Tests step, conclusion=success, Delete-tag skipped, release published.

FIX DIRECTION (couples with making CI green — do NOT just flip the field)

1. steps.test.conclusion -> steps.test.outcome makes the gate real — but flipping it today blocks every future release until the suite is CI-green, which it currently is not (see companion issues: TS golden-fixture collection errors, Java source-code-path crash).
2. So this lands together with CI test-suite partitioning: env-dependent tests must skip cleanly (pytest markers / fixture-presence gating) so "green in CI" is meaningful, then the gate flips to outcome.
3. Belongs to the Epic D floor alongside #197 (PR-time CI) — same suite hygiene, one policy.

DEFINITION OF DONE

• Gate fires on a deliberately broken test (verified on a scratch tag or workflow_dispatch dry run).
• Release workflow green on an honest, fully-run suite; skipped-by-gating tests visibly reported.

Refs: #193 (Epic D), #197.

[rahlk]

Scope consolidation (2026-07-14): this issue now owns the full path to a meaningful CI-green + live gate:

1. Java suite order-dependence — absorbed from test(java): suite is order-dependent — 21/21 in isolation, 15 failures in full-suite runs (global JAVA_HOME mutation / shared cache suspects) #258 (21/21 isolated vs 15 full-suite failures in test_java_sitter; suspects: global os.environ["JAVA_HOME"] mutation in _get_codeanalyzer_exec, shared .codeanalyzer cache, cross-family pollution).
2. TS golden-fixture presence gating — absorbed from test(typescript): golden-fixture tests error instead of skipping when the gitignored fixture is absent (CI + fresh clones) #257 (~23 collection errors in CI/fresh clones must become clean SKIPs or a generated fixture).
3. Source-analysis witness tests — fix(java): source-code analysis crashes with Path(None) — JDK cache resolution assumes a project dir #256 closed as won't-fix (mode unsupported): remove or skip-gate test_get_symbol_table_source_code and test_get_fields_variable_initializers.
4. Only then flip the gate: steps.test.conclusion -> steps.test.outcome, verified against a deliberately broken test on a scratch tag.