fix(swift): preserve declaration identity and compatible call edges

[DavidHLP]

Summary

Refs #2061. Builds on merged #2342 and enables signature-qualified callable identities for Swift only. Bare node names are preserved.

• Distinguishes labels, parameter types, generic and extension requirements, static/class dispatch, async declarations, qualified type paths, and explicit return types.
• Resolves compatible calls by labels, arity, defaults, and trailing closures. Ambiguous compatible overloads are retained with candidate counts; this does not add type inference.
• Persists an uncapped Swift selector separately from the bounded identity so a hashed signature remains callable after serial, parallel, and incremental indexing.
• Filters Swift candidates before applying the output limit; unrelated definitions sharing a bare name cannot discard a unique compatible call.
• Uses index format 6 to rebuild older indexes once and replace collided nodes and stale call edges. This also rebuilds pre-merge format-5 indexes that still carry invented image registry hosts.
• Removes the unrelated Windows Cypher stress adjustment and redundant opt-in validation material. MCP presentation assertions now run in the default test suite.

This remains a large change (26 files, +2969/-77 against the current base), above CONTRIBUTING.md's recommended PR size. The remaining changes implement and test this single Swift identity boundary, its call resolution, and persisted migration.

AI assistance: This update was prepared with an AI agent acting on behalf of DavidHLP.

Validation

Current source head: 4ab447f8dcc75059e562c7d9afdc603d054eae33, including upstream main a7158ac2f48ca646b4527341b76f930f2aeff87e.

Latest main integration validation in Linux x86_64 Docker:

• UBSAN_OPTIONS=halt_on_error=1 scripts/test.sh --suites index_format: all 6 tests passed with ASan/UBSan, including the retained Swift migration cases and image migration from formats 2 and 5.
• scripts/lint.sh --ci CLANG_FORMAT=clang-format-20 "CPPCHECK=cppcheck -j4": passed.
• git diff --check: passed.

The implementation validation below was performed before this latest merge, at source head a9e56d92fd36190598cffbbddf1e6ef47cb98fac (Docker product-code snapshot 5142a753433e89edcfbffbcd7a4c6169b6f64c68). It is not a fresh full test run of the current head.

Independent Linux x86_64 Docker checks use the repository's canonical build/test/lint scripts. Official Swift 6.0.3 typechecks all four independent input groups. The original main, previous PR head, and revised implementation are compared for the reported fake caller, static/instance identity, constrained extensions, capped signatures, and a large same-name bucket. The new regression cases were observed failing before the correction.

Before the latest main integration:

• Production build and assertions over all four independent CLI fixture groups passed.
• scripts/test.sh --suites callable_sig,registry,index_format,extraction: 577 tests passed.
• Focused Swift extraction/pipeline and MCP cases: 44 tests passed with UBSAN_OPTIONS=halt_on_error=1. These overlap the suite run and are not 44 additional distinct tests.
• scripts/test.sh --contracts-only: all contracts passed in a Docker container with --init.
• scripts/lint.sh --ci CLANG_FORMAT=clang-format-20 "CPPCHECK=cppcheck -j4": passed, including no-skips, formatting, cppcheck, NOLINT, and memory-core checks.
• Local DCO check of the pushed commit range passed.

The broader extraction run emits ObjectScript/Perl UBSan diagnostics and is not sanitizer-clean. Those paths are outside this change. Full local cross-platform tests and TSan were not rerun.

GitHub checks for the current source head have not completed; no completed current-head matrix is claimed.

Maintainer review is pending. Passing checks are not maintainer approval.

Review focus

• Swift declaration spelling and separation from call compatibility metadata.
• Selector ownership through compact/spill and serial/parallel/incremental persistence.
• Conservative candidate handling and the format-6 rebuild boundary.

Checklist

• Original fake-caller behavior and additional boundary failures reproduced independently.
• Necessary regressions included in default suites.
• Unrelated Cypher adjustment and duplicate opt-in drivers removed.
• Final targeted Docker integration validation complete.
• Current-head GitHub checks complete.
• Maintainer review complete.

[github-actions]

Thanks for opening this — it has been seen, and it is queued.

This note is automated, but it is not a brush-off: it exists so you know where your PR stands instead of having to guess from silence.

Current review status: working through a backlog. 0.9.1-rc.1 is out, so the release freeze that held reviews is over — but it left a large queue of open pull requests behind it, and we are reading through them oldest-first. The background is in discussion #1144.

What that means for this PR, concretely:

• It will not be closed for inactivity. No stale bot touches pull requests here.
• It may still sit a while before a human reads it. That is on us, not on you.
• Older PRs are read first, so a recent one is not being skipped — it is behind a queue.

Things that will genuinely speed it up whenever review does happen:

• Keep it rebased on main — the tree is moving quickly right now, and a conflicting branch cannot be reviewed as the diff you intended.
• Get CI green, or say which failures you believe are pre-existing.
• Keep the change to one claim. Bundled features and refactors get split before they get merged, which costs you a round trip.
• Every commit needs a sign-off (git commit -s) — CI enforces DCO.

If this fixes a bug, a reproduction we can run is worth more than a description of the symptom.

Thanks for contributing, and sorry in advance for the wait.

[DeusData]

Thank you for the detailed status update and for clearly distinguishing the actual PR head from unpublished work and unverified results. The changed-file scope includes callable identity, resolution and persisted metadata, so we need more time for a complete review together with the parent change. This remains queued for deeper review; this comment is not an approval or a request for another routine rebase. The queue is full, and we appreciate your patience and the care taken to document the remaining work.

[DavidHLP]

I've finished the Swift fixes on top of #2342. The current head is 35533b2674a09e2e6e9a066faf52e3fb8ccdaada; the code was tested at 10f47697, and the last commit only updates the validation notes.

The two remaining collisions now have separate identities: A.Item versus B.Item, and functions that differ only in their declared return type. The tests reproduce each collision before the fix, then check separate nodes, source locations and outgoing calls, including parallel indexing and reopening the index. Call resolution still keeps all compatible candidates rather than guessing from types.

The main thing I'd like feedback on is the identity spelling: qualified types use /, explicit returns use =>Type, and format4 rebuilds older indexes once. The implementation and migration tests are in callable_sig.c, registry.c and test_index_format.c.

On remote-dev, 909 focused tests and 328 pipeline TSan tests passed, along with the separate graph and MCP checks, production build and CI lint. There are still two ObjectScript UBSan reports, so the focused run isn't sanitizer-clean. The full C run stops at the Scoop metadata precheck, full clang-tidy still reports errors, and the native CLI crashes at startup with the same stack seen in the earlier main comparison. Current macOS, Windows and Ubuntu CLI checks haven't been run.

Test commands and full logs are available here. I removed the duplicate progress comments; their original text is archived. This is ready for review, with the remaining checks and approval still pending.