Remove deprecated Make flow

[mguthaus]

The Bazel flow is now the only maintained build flow. PR #71 removed the docker_pkg image tracking from MODULE.bazel, which is the source of truth that setup.sh / runorfs.sh / runorfs_ni.sh / tools/bump_orfs.sh all grep for. Those scripts are now broken (they end up running docker pull ""), and nobody is updating them.

The Make flow is deprecated as of the bazel-orfs HEAD bump (commit d9f8b757) and should be removed.

Files / paths to delete

• setup.sh
• runorfs.sh
• runorfs_ni.sh
• tools/bump_orfs.sh (or rewrite to validate just the bazel-orfs submodule pin)
• Makefile (top-level — wraps OpenROAD-flow-scripts/flow/Makefile)
• settings.mk
• OpenROAD-flow-scripts/ git submodule + .gitmodules entry + symlinks (scripts/, util/, platforms/)
• designs/*/*/config.mk (per-design Make config)
• designs/src/*/verilog.mk (per-design Make-flow RTL selection)
• designs/src/*/dev/setup.sh (RTL regeneration entry points used by update-rtl)
• docs/make-flow.md
• README link to docs/make-flow.md
• CLAUDE.md "Make Flow Setup" / "Make Flow (deprecated)" / "Key Relationships (Make Flow)" sections

Things to migrate first

• update-rtl (regenerate Verilog from upstream sources) — currently a Make-flow target. Bazel flow handles this via bazel build --define update_rtl=true ... and per-design rtl_dev_gen genrules, so the functionality already exists; just need to confirm every design has the Bazel path wired before deleting designs/src/*/dev/setup.sh.
• tools/bsg_fakeram integration — generate-sram skill uses Make-flow paths; verify it works without settings.mk / OpenROAD-flow-scripts symlinks.

Out of scope

• Changes to per-design BUILD.bazel files (these stay; they are the Bazel-flow source of truth).
• The bazel-orfs / ORFS submodule pins (separate concern).

Tracking: see docs/make-flow.md for the deprecation notice and the bazel-orfs PR #71 for the upgrade that broke the Docker-image grep.