*: Phase 1 of FrostDB removal — ClickHouse-only cmd path

[thorfour]

Summary

Phase 1 of removing FrostDB from Parca (tracking issue / Discord thread). Collapses the dual-path init in pkg/parca/parca.go to ClickHouse-only and promotes the ClickHouse flags out of FlagsHidden so they're visible in --help.

• Removed FrostDB-only flags: --storage-active-memory, --storage-enable-wal, --storage-snapshot-trigger-size, --storage-row-group-size, --storage-index-on-disk, the experimental --iceberg-storage hidden flag, and --clickhouse-enabled (the toggle is gone since ClickHouse is now the only backend).
• --enable-persistence survives but now controls only the local badger metastore — profile data lives in ClickHouse.
• pkg/ingester/ and pkg/parcacol/querier.go are dead from the cmd path but kept in tree because the existing test suite still exercises them; they get removed when those tests are reworked against testcontainers (Phase 3).
• dynparquet/pqarrow imports are still load-bearing on the ClickHouse path (schema definition, normalizer, profilestore) — those are untangled in Phase 2.
• Benchmark_WriteRaw is now b.Skip'd since it drove Run() which now requires ClickHouse. Restored via testcontainers in Phase 3.
• snap/parca-wrapper no longer plumbs --storage-active-memory. Wiring full ClickHouse config (address/credentials) into the snap is a separate follow-up.
• README.md regenerated via make README.md.

Follow-ups

• Phase 2 — untangle dynparquet + pqarrow from pkg/normalizer/, pkg/profile/schema.go, pkg/profilestore/profilecolumnstore.go, pkg/query/{flamegraph_arrow,table,columnquery}.go.
• Phase 3 — rework the FrostDB-backed tests in pkg/parca/parca_test.go, pkg/profilestore/profilestore_test.go, pkg/ingester/ingester_test.go, pkg/query/{query,columnquery}_test.go against testcontainers ClickHouse; delete pkg/ingester/ and pkg/parcacol/querier.go.
• Phase 4 — go mod tidy; drop frostdb and iceberg-go from go.mod.
• Snap follow-up — add clickhouse-* snap config keys + hooks so the snap can boot a usable parca without command-line overrides.

Test plan

• go build ./...
• go vet ./...
• go test -short ./...
• CI green
• Manual smoke: parca boots against a local ClickHouse and ingests a profile
• Confirm parca --help reads cleanly (regenerated README)

🤖 Generated with Claude Code

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