feat(WP-0003c): context adapters, first ActivityDefinition, full test suite

T51: ContextResolver ABC + CONTEXT_RESOLVER_REGISTRY; resolve_context activity
updated to dispatch via registry (warns + binds {} on failure, never aborts run).
T52: RepoScopingContextResolver with 5-min in-process cache.
T53: StateHubContextResolver (no cache) for domain_summary and repo_sbom_status.
T54: activity-definitions/weekly-sbom-staleness.md (Monday 09:00 Berlin, cron
trigger, flag-stale-sbom rule at >30 days) + tasks/sbom-rescan.md template.
T55: 51 parametrized evaluator tests — all whitelisted operators, unsafe
expression rejection, empty condition, missing attribute, nested context access.
T56: 15 executor safety tests — UntrustedFieldError, object-type rejection,
injection fixture, LLM retry on bad JSON, review_required field.
T57: 6 integration tests — parses real definition, evaluates rule per-repo
(stale/fresh boundary), emits via NullSink, verifies spawn log entries.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tasks/sbom-rescan.md

@@ -0,0 +1,26 @@
+---
+id: sbom-rescan
+title_template: "Run SBOM rescan — {target_repo}"
+default_priority: medium
+default_labels: ["sbom", "security", "automated"]
+default_assignee: null
+---
+
+# SBOM Rescan Task Template
+
+## Description
+
+An SBOM rescan is overdue for `{target_repo}`. The repository's last recorded
+SBOM scan exceeds the 30-day staleness threshold.
+
+## Steps
+
+Run the following from the workstation:
+
+```sh
+cd ~/the-custodian/state-hub
+make ingest-sbom REPO={target_repo} SCAN=1
+```
+
+The scan updates `last_sbom_at` in the State Hub and ingests the new SBOM into
+the licence and dependency tracking tables.