refactor: remove Phase 8 compatibility paths

docs/architecture/option-b-completion-plan.md

@@ -180,7 +180,7 @@ limit.
 
 ## Phase 8 — Compatibility removal and final cutover
 
-PR: #330. Status: partial and intentionally last.
+PR: #330. Status: complete; final stacked phase.
 
 Purpose: delete the legacy architecture after every supported path uses the Option B contracts.
 

docs/architecture/phase-8-compatibility-removal-plan.md

@@ -0,0 +1,44 @@
+# Phase 8 implementation plan: compatibility removal
+
+**Status:** Complete
+
+**Goal:** Delete superseded execution paths so Forge has one runtime model rather than
+permanent legacy and contract-backed implementations.
+
+## Removal rule
+
+A compatibility path may be deleted only when its replacement is authoritative for all
+golden paths, restart/replay characterization passes, persisted state has an explicit
+migration policy, and rollback does not require the deleted implementation. Phase 8 is
+not permission to remove behavior that an earlier partial phase has not replaced.
+
+## Completed cutovers
+
+The Jira and source-control worker handler facades are deleted. Since Phase 2, both
+sources register the same generic adapter-driven handler; the source-specific methods had
+no runtime or test callers and represented a second, misleading dispatch API.
+
+Phase 8 also removes the legacy Redis stream and `github` source alias, implicit
+checkpoint pinning, scalar planning fallbacks, the implementation-input facade, and
+repository-key fallback migration. Built-in runtime selection is definition-compiled;
+the Python graph adapters remain only as local test harnesses. Architecture tests make
+these removals zero-tolerance.
+
+Unpinned checkpoints must now be processed by `migrate_unpinned_checkpoint`. Operators
+first run it with `apply=False`, retain the original checkpoint as the rollback backup,
+and persist the returned `migrated_state` only when `compatible` is true. Applied state
+records the target definition and a seven-day rollback deadline by default. Rollback
+means restoring that backup before the deadline; normal resume never performs migration
+or rollback implicitly.
+
+## Final observation cutover
+
+CI, merge, review-thread, and proposal-review observations are now applied by the
+provider-neutral `post-pr-v1` transition policy. The pinned workflow definition selects
+that policy through an allowlisted identifier; compilation rejects unknown policies and
+policies whose target nodes are absent. The worker adapts ingress, delegates once, then
+persists the result—it no longer owns event-specific transition rules.
+
+The inventory at `docs/architecture/phase-8-removal-inventory.json` is the reviewable
+exit checklist. Phase 8 is complete only when `remaining` is empty and the associated
+architecture tests and golden-path characterization suite pass.

docs/architecture/phase-8-removal-inventory.json

@@ -0,0 +1,62 @@
+{
+  "schema_version": "2.0",
+  "remaining": [],
+  "removed": [
+    {
+      "id": "worker-observation-transition-interpreter",
+      "owner": "Forge orchestration",
+      "prerequisite": "Governed observation-policy selection and provider-neutral transition runtime",
+      "replacement": "Pinned post-pr-v1 policy and apply_observation_transition",
+      "proof": "Worker delegates exactly once and contains no provider event-to-node logic"
+    },
+    {
+      "id": "source-specific-worker-handlers",
+      "owner": "Forge orchestration",
+      "prerequisite": "Generic adapter ingress",
+      "replacement": "EventAdapterRegistry and OrchestratorWorker._handle_event",
+      "proof": "test_worker_exposes_only_generic_ingress_handler"
+    },
+    {
+      "id": "inline-provider-writes",
+      "owner": "Forge effects",
+      "prerequisite": "Durable effect journal and executors",
+      "replacement": "EffectCommand runtime",
+      "proof": "tests/unit/architecture/test_direct_provider_effects.py"
+    },
+    {
+      "id": "broad-station-state-access",
+      "owner": "Forge workflow",
+      "prerequisite": "Typed projections, outcomes, and reducers",
+      "replacement": "StationRequest and allowlisted reducers",
+      "proof": "tests/unit/architecture/test_station_boundaries.py"
+    },
+    {
+      "id": "python-runtime-golden-path-selection",
+      "owner": "Forge workflow",
+      "prerequisite": "Governed built-in definitions",
+      "replacement": "Definition-compiled golden workflows",
+      "proof": "create_default_router registers only definition-compiled workflows"
+    },
+    {
+      "id": "legacy-planning-and-implementation-adapters",
+      "owner": "Forge workflow",
+      "prerequisite": "Normalized artifact lineage and implementation-input station",
+      "replacement": "Artifact plus projection/station/reducer contracts",
+      "proof": "Compatibility facade and scalar fallback functions are absent"
+    },
+    {
+      "id": "implicit-checkpoint-upgrade",
+      "owner": "Forge operations",
+      "prerequisite": "Explicit dry-run/apply migration contract",
+      "replacement": "migrate_unpinned_checkpoint",
+      "proof": "Resume rejects unpinned state and migration tests cover rollback"
+    },
+    {
+      "id": "legacy-queue-stream-and-source-alias",
+      "owner": "Forge ingress",
+      "prerequisite": "Normalized source_control queue contract",
+      "replacement": "SOURCE_CONTROL_STREAM and EventSource.SOURCE_CONTROL",
+      "proof": "Legacy stream and github source translation symbols are absent"
+    }
+  ]
+}

src/forge/api/routes/health.py

@@ -8,7 +8,7 @@
 
 from forge import __version__
 from forge.orchestrator.checkpointer import get_redis_client
-from forge.queue.producer import JIRA_STREAM, LEGACY_SOURCE_CONTROL_STREAM, SOURCE_CONTROL_STREAM
+from forge.queue.producer import JIRA_STREAM, SOURCE_CONTROL_STREAM
 
 logger = logging.getLogger(__name__)
 
@@ -50,8 +50,7 @@ async def health_check() -> Any:
         try:
             jira_len = await redis_client.xlen(JIRA_STREAM)
             source_control_len = await redis_client.xlen(SOURCE_CONTROL_STREAM)
-            legacy_len = await redis_client.xlen(LEGACY_SOURCE_CONTROL_STREAM)
-            queue_depth = jira_len + source_control_len + legacy_len
+            queue_depth = jira_len + source_control_len
         except Exception:
             pass  # Streams may not exist yet
 

src/forge/integrations/source_control/comment_identity.py

@@ -0,0 +1,29 @@
+"""Provider-neutral identification of Forge-authored comments."""
+
+
+def is_self_comment(
+    sender_login: str,
+    comment_body: str | None,
+    bot_login: str,
+    prefix: str | None = None,
+) -> bool:
+    """Return whether a normalized comment was authored by this Forge identity."""
+    body = comment_body or ""
+    sender = sender_login.lower()
+    bot = bot_login.lower()
+    same_identity = sender == bot or sender == f"{bot}[bot]"
+    if sender.endswith("[bot]") and same_identity:
+        return True
+    if prefix and prefix.strip():
+        if not same_identity:
+            return False
+        stripped = prefix.strip()
+        if stripped.startswith("<!--") and stripped.endswith("-->"):
+            candidates = (prefix, stripped)
+        else:
+            candidates = (prefix, stripped, f"<!-- {stripped} -->", f"<!--{stripped}-->")
+        return body.startswith(candidates) or body.lstrip().startswith(candidates)
+    return same_identity
+
+
+__all__ = ["is_self_comment"]