Discourage LLMs from touching fdctl

[ripatel-fd]

No description provided.

[greptile-jt]

Greptile Summary

Documentation-only PR that steers contributors (and LLMs) away from the legacy Frankendancer surface (fdctl, fddev, discoh) and toward the pure-C Firedancer build target.

• CLAUDE.md: removes the "focus on firedancer-dev / discof instead" carve-out and simply directs readers to avoid Frankendancer-specific parts.
• CONTRIBUTING.md: bumps the documented minimum compiler from GCC 8.5 (2024-Jul) to GCC 11 (June 2026); renames the primary build target from "Frankendancer (fdctl)" to "firedancer"; adds "atomic 32 byte load/store" to the required Haswell feature set; drops the list of experimental targets (musl/macOS/FreeBSD/SVM, arm64/ppc64le, sBPFv1/v2).
• contrib/containers/README.md: replaces make -j all fdctl fddev with make -j to match the new default.
• doc/build-system.md: refreshes the example ldd output to use bin/firedancer instead of bin/fdctl, with an updated library list.

No source code, build rules, or runtime behavior are touched. One minor latent inconsistency worth flagging for a future docs pass (not introduced by this PR): contrib/containers/README.md still advertises GCC 8/9/10 containers in its header while CONTRIBUTING.md now states GCC 11 is the minimum supported version.

Confidence Score: 5/5

• Documentation-only changes with no impact on build or runtime behavior — safe to merge.
• All four edits are prose updates to Markdown docs that align guidance with the current Firedancer-first direction. No source files, Makefiles, configs, or generated artifacts are touched, so there is no functional risk.
• No files require special attention.

Important Files Changed

Filename	Overview
CLAUDE.md	Tightens guidance for LLMs: removes the carve-out that pointed contributors at Firedancer equivalents (firedancer-dev, discof) and now simply tells them to avoid Frankendancer-specific parts (fdctl, fddev, discoh). No code impact.
CONTRIBUTING.md	Updates compiler compatibility section: bumps minimum GCC from 8.5 (2024-Jul) to GCC 11 (June 2026), renames the primary build target from "Frankendancer (fdctl)" to "firedancer", and adds "atomic 32 byte load/store" to the Haswell feature set. Drops the list of experimental targets (musl, macOS, FreeBSD, SVM, arm64, ppc64le, sBPFv1/v2). Docs-only.
contrib/containers/README.md	Replaces make -j all fdctl fddev with make -j in the container build instructions, aligning with the move away from explicit Frankendancer targets.
doc/build-system.md	Updates the example ldd output to reference build/native/gcc/bin/firedancer instead of bin/fdctl, with a corresponding refreshed library list (adds libmvec.so.1, drops librt/libdl/libpthread). Documentation refresh only.

_{Last reviewed commit: 7672c1b}

[github-actions]

Performance Measurements ⏳

Suite	Baseline	New	Change
backtest mainnet-406545575-perf per slot	0.09004 s	0.089946 s	-0.104% ✅
backtest mainnet-406545575-perf snapshot load	1.786 s	1.784 s	-0.112% ✅
backtest mainnet-406545575-perf total elapsed	90.039632 s	89.94638 s	-0.104% ✅
firedancer mem usage with mainnet.toml	1138.39 GiB	1138.39 GiB	0.000% ✅

[Copilot]

Pull request overview

This PR updates repository documentation to steer tooling/LLM guidance away from Frankendancer (fdctl/fddev) and toward Firedancer (firedancer), and refreshes build instructions/examples accordingly.

Changes:

• Replace fdctl references in build-system docs with firedancer (e.g., ldd example output).
• Update contribution/build compatibility text and supported target wording.
• Simplify container build instructions to use the default make -j target set.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
doc/build-system.md	Switches the dynamic-linking example from fdctl to firedancer.
CONTRIBUTING.md	Updates compiler compatibility and target/CPU feature-set documentation for the firedancer target.
contrib/containers/README.md	Simplifies build command to make -j in container instructions.
CLAUDE.md	Tightens guidance to avoid Frankendancer-specific components.