feat(context): wire headroom proxy and injection budget shadow paths

Add fail-open headroom provider routing for goosed sync, context-budget
planning with shadow telemetry events, and fix portal-resume smoke to skip
force_deep_reasoning by default so session round-trip checks stay fast.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/goose-v149-canary.env.example

@@ -23,3 +23,13 @@ MEMORY_CANDIDATE_ENABLED=0
 
 # Goose v1.49 local session DB (isolated from production memind_sessions)
 # GOOSE_SESSION_DB_URL=postgresql://john@127.0.0.1:5432/goose_sessions_v149_dev
+
+# Headroom context compression (Phase 1, local loopback only)
+# MEMIND_HEADROOM_MODE=off
+# MEMIND_HEADROOM_PROXY_BASE_URL=http://127.0.0.1:8787/v1
+# MEMIND_HEADROOM_UPSTREAM_BASE_URL=http://127.0.0.1:18036/v1
+# HEADROOM_OUTPUT_SHAPER=0
+
+# Context injection budget (Phase 2, default off — does not open memory injection)
+# MEMIND_CONTEXT_BUDGET_MODE=off
+# MEMIND_CONTEXT_BUDGET_MAX_CHARS=12000