chore(build-engine): route production .fbuild walks through fbuild-paths

[zackees]

Fourth ratchet batch for #1349. Allowlist 33 → 28.

Scope: production sites only

The five fbuild-build-engine files here are the skip-lists and path walks
that decide what a build looks at:

file	what it was doing
build_fingerprint/fast_path.rs	FAST_PATH_EXCLUDES const array
source_scanner.rs	scanner skip-list const array
framework_libs.rs	two matches! arms
compiler.rs	ancestor walk comparing the directory name
symbol_analyzer/mod.rs	ELF search over <.fbuild>/<build>

FBUILD_DIR_NAME is a const &str, so it drops straight into the const
arrays and works as a const pattern in matches! — no restructuring needed.

These are worth more than a spelling fix. A skip-list that disagrees with the
real directory name silently stops excluding the build tree, and a warm build
then starts fingerprinting its own output.

The crate's five test-fixture files are deliberately left for the next
batch. They are a different kind of change — hand-rolled layouts inside
assertions — and mixing ten files of two kinds would bury the production edits
in fixture churn.

Verification, including a near-miss worth recording

Main already carried lint version 0.1.3 (from #1387), so the habitual
0.1.2 → 0.1.3 bump was a no-op. The first clean dylint run could
therefore have been a cached .so still holding the old allowlist — which
would allowlist exactly the five files under test and report zero findings for
the wrong reason.

Bumped to 0.1.4, re-ran: still clean. Then confirmed the lint actually fires
on these files by reintroducing a canary ".fbuild/canary" literal into
source_scanner.rs — exit 1, one finding — and removing it again.

• soldr cargo test -p fbuild-build-engine --lib: 405 passed, 0 failed
• clippy -D warnings: clean

Remaining

28 entries: fbuild-build 12, fbuild-build-engine 5 (tests), fbuild-cli 9, plus
the 2 sanctioned definition sites. fbuild-cli continues to sit out while
#1384 has cli/args.rs open.

Summary by CodeRabbit

• Refactor
  • Centralized internal build-directory path handling to keep directory detection and exclusions consistent across build scanning and analysis.
  • Updated native output discovery to use the shared build-directory naming configuration.
• Chores
  • Removed obsolete path-related lint exceptions.
  • Updated the path validation tool version.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

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Run ID: df88b457-b488-4670-9af5-a61c78b75ad2

📥 Commits

Reviewing files that changed from the base of the PR and between 3445e4f and 3a05043.

📒 Files selected for processing (7)

• crates/fbuild-build-engine/src/build_fingerprint/fast_path.rs
• crates/fbuild-build-engine/src/compiler.rs
• crates/fbuild-build-engine/src/framework_libs.rs
• crates/fbuild-build-engine/src/source_scanner.rs
• crates/fbuild-build-engine/src/symbol_analyzer/mod.rs
• dylints/ban_raw_fbuild_path/Cargo.toml
• dylints/ban_raw_fbuild_path/src/allowlist.txt

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📝 Walkthrough

Walkthrough

The build engine replaces hard-coded .fbuild paths with shared constants across fingerprinting, scanning, framework discovery, and ELF discovery. The raw-path lint package version and allowlist are updated accordingly.

Changes

Fbuild path constant adoption

Layer / File(s)	Summary
Replace hard-coded fbuild paths crates/fbuild-build-engine/src/build_fingerprint/fast_path.rs, crates/fbuild-build-engine/src/compiler.rs, crates/fbuild-build-engine/src/framework_libs.rs, crates/fbuild-build-engine/src/source_scanner.rs, crates/fbuild-build-engine/src/symbol_analyzer/mod.rs	Build-engine path exclusions, workspace detection, and ELF search paths now use shared directory-name constants.
Update raw-path lint enforcement dylints/ban_raw_fbuild_path/Cargo.toml, dylints/ban_raw_fbuild_path/src/allowlist.txt	The lint package version changes to 0.1.4, and five obsolete allowlist entries are removed.

Estimated code review effort: 2 (Simple) | ~10 minutes

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/1349-ratchet-batch4

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