fix(deploy): unblock fake-exporter rebuild — proto bindings + sketchlib-go rename adaptation

[zzylol]

Summary

asap/fake-exporter:dev rebuild was broken from two independent
upstream drift sources. PR #257 (E2 label-axis CPU fix) needed a
post-fix live-cell capture but couldn't get it without this rebuild.
Both blockers fixed; cold-cache docker build now lands a clean image
that the E0 stack accepts.

Blocker A — missing Go bindings under opentelemetry-proto-patch/

The patched metrics.proto adds DDSketch / KLLSketch / CountSketch / CountMinSketch / HLLSketch message types + *DataPoint + *Encoding
enums on top of upstream v1.9.0, but the regenerated .pb.go files
were never committed. Every build hit undefined: mpb.Metric_Ddsketch / mpb.DDSketchDataPoint / ... deep in the patched OTLP gRPC transform
layer.

Fix:

• Regenerated bindings via the upstream Makefile recipe
  (otel/build-protobuf:0.9.0, --go_out=plugins=grpc) over a clean
  v1.9.0 checkout overlaid with the patched .proto files.
• Committed all 10 outputs (11,385 lines, 600 KB) under
  opentelemetry-proto-patch/gen/go/go.opentelemetry.io/proto/otlp/.
  Updated .gitignore to track that subtree (it was previously
  globbed out).
• Added go.opentelemetry.io/proto/otlp => ../../opentelemetry-proto/gen/go/go.opentelemetry.io/proto/otlp to
  deploy/fake-exporter/go.mod. The same replace exists in the
  patched grpc/http exporters' go.mod, but those aren't honored from
  a downstream main module.
• Updated Dockerfile.fake-exporter to COPY opentelemetry-proto/
  into the build context so the relative replace path resolves.
• Wrote opentelemetry-proto-patch/REGEN.md documenting the full
  regeneration recipe so future contributors don't need to reverse-
  engineer the toolchain.

Blocker B — sketchlib-go API rename refactor (PR #53) absorption

The patched OTLP transform files referenced metricdata.*EncodingGob
and mpb.*_ENCODING_GOB enum names that the prior gob→proto rename
had already obsoleted. Once the proto bindings resolved, the build
caught these.

Fix: updated KLL / CountSketch / CountMinSketch encoding-switch arms
in both otlpmetricgrpc/internal/transform/metricdata.go and
otlpmetrichttp/internal/transform/metricdata.go to dispatch on the
post-rename names. CountSketch / CountMinSketch get the additional
Delta arm matching the sparse-delta wire path; KLL keeps a single
Proto arm (no delta defined for KLL).

The actual sketchlib-go PR #53 renames (Add/Insert → Update,
InsertValue → UpdateValue, EstimateCardinality() → Estimate(),
GetValueAtQuantile → Quantile, InsertWeight/InsertBatch/
InsertHashes/BulkInsert → UpdateWeight/UpdateBatch/
UpdateHashes/BulkUpdate) had already been absorbed in
opentelemetry-go-patch/sdk/metric/internal/aggregate/{hllsketch, kllsketch,countminsketch,countsketch}.go and
asap-precompute-go/sketches/hll.go before this round; the rebuild
verifies they're correct.

Files touched

• opentelemetry-proto-patch/gen/go/... — 10 new .pb.go files +
  hand-maintained go.mod (modeled on upstream).
• opentelemetry-proto-patch/.gitignore — track gen subtree.
• opentelemetry-proto-patch/REGEN.md — new.
• opentelemetry-go-patch/exporters/otlp/otlpmetric/{otlpmetricgrpc, otlpmetrichttp}/internal/transform/metricdata.go — Gob → Proto/Delta
  enum switches.
• deploy/fake-exporter/go.mod — replace for the local proto otlp tree.
• deploy/docker/Dockerfile.fake-exporter — copy opentelemetry-proto
  into build context + updated header comment to reference the proto
  restore script.
• PROGRESS.md — companion-changes follow-up entry marking the
  rebuild unblocked.

Verification

Cold-cache build:

docker builder prune -af
DOCKER_BUILDKIT=1 docker build --no-cache \
  -f deploy/docker/Dockerfile.fake-exporter \
  --build-context sketchlib-go=/path/to/sketchlib-go \
  -t asap/fake-exporter:dev .
# → writing image sha256:60101fd5… naming to docker.io/asap/fake-exporter:dev DONE 0.1s

Image runs against the live E0 stack (b3-delta + e2e-overlay, N=1):

docker compose -f deploy/docker-compose/base.yml \
  -f deploy/docker-compose/agents-N1.yml \
  -f deploy/docker-compose/baseline-b3-delta.yml \
  -f deploy/docker-compose/e2e-overlay.yml \
  up -d --force-recreate fake-exporter
# → Container docker-compose-fake-exporter-1  Started

docker logs --since 60s docker-compose-fake-exporter-1
# control plane listening on 0.0.0.0:7700 …
# raw-tee writing ground truth under /var/asap/cold
# fake-exporter sdk config: window=15s agg=default projection=""
# fake-exporter starting (synthetic): metric=http_requests_total cardinality=100000 freq_hz=100.0 schema=4x10x25x10
docker ps --filter "name=fake-exporter"
# Up 30 seconds   (no errors logged)

go build ./... && go test ./... clean for
opentelemetry-go/sdk/metric/ and asap-precompute-go/.

Test plan

• Cold-cache docker build succeeds end-to-end.
• Image runs cleanly under the b3-delta + e2e-overlay compose stack
  for ≥30s with no errors.
• go build ./... clean in patched opentelemetry-go/sdk/metric/
  and asap-precompute-go/.
• go test ./... clean in opentelemetry-go/sdk/metric/ and
  asap-precompute-go/.
• (Open question for downstream) Re-run E2's run-sdk-cost-eval.sh
  label-axis sub-sweep against the rebuilt image and confirm
  keep zone,rack cell drops from ~0.749 c → ~0.22 c per the bench
  table in docs/eval-label-axis-cpu-rootcause.md.